taxonID	type	description	language	source
03CA2B5BF743735EFFDCFF67FD2C98C5.taxon	description	In most cases the hairs show a single length, but in some species hairs of two different lengths are present (e. g., sepals of T. laevigatus, branchlets, leaves and inflorescences of T. sinclairii and T. balgooyi). The hairs vary from whitish to golden yellowish, from short to long and from soft silky to stiff hispid and sometimes they have a somewhat bulbose base.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7497354FFDCFCE9FA369263.taxon	distribution	Distribution — Thailand, Malay Peninsula, Sumatra, Java, Bali. Habitat & Ecology — Lowland evergreen (often dipterocarp) forests, growing in understorey on limestone, along streams or on hill slopes. Altitude: 0 – 600 m. Flowering and fruiting: all year round. Notes — 1. A species variable in shape and size of the leaves. It shows similarities with T. wildeorum, from which it can easily be differentiated by its racemose or paniculate pistillate inflorescences (vs pistillate flowers always inserted in leaf axils and the pistillate sepals always strongly accrescent in T. wildeorum). 2. One specimen (P. E. Schmutz 524, Lesser Sunda Islands, Flores) with elliptic and dark brownish to greyish leaves and a short (c. 1.5 cm) staminate peduncle, seems to be an intermediate form between T. aurantiacus and T. hartleyi (endemic to New Guinea), and even the location of the collection is between W Malesia and New Guinea. Since no other specimens are known and T. hartleyi is a poorly understood species, this specimen cannot be accurately identified and the Lesser Sunda Islands is here not included in the distribution of T. aurantiacus.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7487356FFDCFF67FD919F92.taxon	description	This species strongly resembles T. merrillii and T. villosus, but differs by its appressed stellately bundled hairs, cordate bracts subtending the pistillate flowers and staminate flowers with 5 instead of 3 stamens. — Type: M. M. J. van Balgooy 7102 (holo L; iso K, KEP, SAN), Malaysia, Johor, Endau-Rompin, Kuala Jasin, N 2 ° 32 ' E 103 ° 22 '. Paratypes: Sinclair 10598 (K, SING; E, NY not seen), Malaysia, Johor, Gunung Panti, Waterfall, Lombong; KEP FRI (Kamarul Hisham et al.) 73820 (K, KEP, SAN, SING; BKF not seen), Malaysia, Johor, Endau-Rompin S. P., Bagoh camp area; KEP FRI (Kamarul Hisham et al.) 73826 (KEP), Malaysia, Johor, Mersing, Endau-Rompin S. P., trail to Kuala Kembah camp from Bagoh; Stone 8719 (KLU), Malaysia, Johor, Kota Tinggi, Ayer Terjun. Shrubs or small trees, 2 – 3 m tall, dbh 1.5 – 3 cm; flowering branches 3 – 4 mm diam. Indumentum consisting of 2 layers of hairs (except on sepals and upper surface of leaves and bracts, these glabrous or with only 1 layer of hairs), upper layer hispid, with simple long and rigid golden hairs, lower layer of stellately bundled hairs consisting of 3 – 5 tiny, appressed, whitish hairs originating from one papillose point. Outer bark c. 0.1 mm thick, dark brownish to greyish, hairy, often slightly fissured; inner bark 0.1 – 0.2 mm thick, whitish to reddish to brownish, often with sap (solidified when dry); wood creamy, reddish brown. Stipules subulate, c. 0.5 mm long, caducous. Leaves: petiole terete, 1.5 – 6 cm long, 1 – 1.5 mm diam, hairy; blade oblong to oblanceolate, 12 – 23 by 1.5 – 6 cm, chartaceous, base cuneate to acute, with 2 nipple-like glands adaxially, margin distantly serrate, teeth small, falcate, apex acuminate to caudate, upper surface medium green, slightly bullate, papillose hispid (no stellate hairs), lower surface pale green, papillose hispid and with stellately bundled hairs on venation; venation penninerved, midrib slightly elevated above and distinctly elevated beneath, nerves 9 – 11 pairs, curved and bow-shaped, narrowed and connected along margin, veins reticulate, often obscure above. Inflorescences: staminate ones pyramidal paniculate or racemose, sometime cauliflorous, rachis at least up to 9 cm long, c. 1 mm diam (lower part), hispid and with stellately bundled hairs; bracts lanceolate, up to 7.5 by 1.3 mm, sparsely papillose hispid above, hispid and with stellately bundled hairs beneath; pistillate ones often single-flowered, peduncles 4 – 6 cm long, c. 0.6 mm diam (evenly wide throughout), sparsely hispid; bracts in lower part often 1.3 – 1.8 by 0.4 – 0.5 cm, hispid and with sparse stellately bundled hairs; bracts subtending the pistillate flower cordate, 1.5 – 2.1 by 0.6 – 1.2 cm, palmately veined, sparsely hispid above and hispid and with sparse stellately bundled hairs (often along veins) beneath. Staminate flowers c. 7 mm diam; pedicel indiscernible; sepals elliptic, 1 – 1.5 by c. 1 mm, pale green, sparsely papillose hispid outside, glabrous inside; petals elliptic, c. 3.3 by 2.5 mm, red to maroon, both sides glabrous, sometimes with a few pustules; disc lobes glandular, 0.25 – 0.3 by 0.3 – 0.6 mm, deep purple, apex rounded, slightly recurved; stamens 5, androphore c. 0.7 mm long, 5 - cleft at apex; anthers ellipsoid, each theca 0.5 – 0.6 mm long, connectives apically with dark purplish droplets (or expanded cells) with secretion. Pistillate flowers c. 1.2 mm diam; pedicel less than 5 mm long; sepals triangular, c. 6.5 by 4.5 mm, apex acuminate, hispid outside, sparsely hispid and with sparse stellately bundled hairs (often along veins) inside; petals orbicular, 6 – 7 by 5 – 6.8 mm, maroon; disc not seen; ovary c. 1.2 mm diam, sparsely hairy; style c. 0.2 mm long, stigmas deeply divided, free parts c. 1.5 mm long. Fruits: sepals (remnants) persistent, 1.3 – 1.5 by 0.55 – 1 mm, with sparse stellately bundled hairs outside, glabrous inside; columella 5.5 – 7 mm long; cocci white, with a few hairs when young and nearly glabrous when mature; wall c. 0.65 mm thick, exocarp not detaching. Seeds c. 6 mm diam, brown when dry. Distribution — Malay Peninsula (endemic). Habitat & Ecology — Lowland primary (dipterocarp) rainforest on clay soil on hillside or riverside. Flowering: March to April, July; fruiting: July. Note — The only species in Malesia that has stellately bundled hairs, which makes it quite unique (T. reidioides in Thailand and Indochina also has stellately bundled hairs). The cordate bracts of the pistillate flowers are also distinct. The pistillate disc was not seen because it was covered by petals in the only flower present on the available material.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF74B7356FFDCF9E7FB1E9DF9.taxon	description	Trigonostemon beccarii Ridl. (1925) 89; Jabl. (1963) 165; Airy Shaw (1981) 353. — Type: Beccari PS 965 (K, L), Sumatra, Padang, Sungei Buluh. Trigonostemon longisepalus Ridl. (1925) 89; Jabl. (1963) 165. — Type: Brooks 8274 (holo K), Sumatra, Lubok Tandai. Shrubs; flowering branches 1.6 – 4.5 mm diam, sometimes hollow. Outer bark 0.1 – 0.2 mm thick, brownish to greyish, smooth; inner bark 0.1 – 0.2 mm thick, dark reddish brown; wood white to pale reddish brown. Stipules falcate, 0.5 – 0.7 mm long, glabrous. Leaves: petiole 0.25 – 1.5 cm long, grooved above, glabrous to glabrescent; blade oblong to oblanceolate, 8 – 28 by 1.5 – 7 cm, base cuneate, adaxially 2 glands present but caducous, margin slightly distantly serrate, apex acuminate, upper side dark greenish, lower side pale green, both sides glabrous; midrib slightly raised on both sides, nerves 10 – 14 pairs, very slightly raised beneath, often obscure, small nerves reticulate, obscure. Inflorescences bisexual, axillary to subterminal, often 1 pistillate flower on the top and few short scorpioid cymes (glomerules) of staminate flowers along the Map 3 Distribution of Trigonostemon balgooyi R. Y. Yu & Welzen (●); T. beccarii Ridl. (■); T. calcicolus (R. I. Milne) R. Y. Yu & Welzen (★); T. diffusus Merr. (▲); T. dipteranthus Airy Shaw (▼); T. filiformis Quisumb. (◆). rachis below; rachis 3 – 12 cm long, 0.5 – 0.7 mm diam, glabrous; bracts elliptic to lanceolate, 0.7 – 1.5 by 0.3 – 0.6 mm, glabrous to pubescent, apex acuminate to rounded. Staminate flowers c. 4.5 mm diam; pedicel c. 3.5 mm long, c. 0.3 mm diam, glabrescent; sepals elliptic, c. 1 by 0.7 mm, apex rounded, slightly ciliate on margin, glabrescent outside; petals elliptic, 1.5 – 2.2 by 1.2 – 1.5 mm, margin entire, apex rounded, glabrous outside, rough and papillose inside; disc lobes semi-orbicular to nearly lanceolate, c. 0.5 by 0.5 mm, apex rounded, glabrous; stamens 5, androphore c. 0.5 mm long, 5 - cleft at the top, anthers ovoid to ellipsoid, c. 0.6 mm long, free, thecae slightly divaricate at apex, connectives apically with numerous droplets (expanded cells) with secretion. Pistillate flowers 2.5 – 3.5 mm diam; pedicel slightly thickened towards apex, c. 6 mm long, apically 0.7 – 1 mm diam when flowering, accrescent to 2.5 cm long and apically 2 mm diam when fruiting, glabrous to glabrescent; sepals ovate, 1.4 – 1.7 by 1 – 1.5 mm, apex acute, slightly pubescent to glabrescent outside; petals (remnants) nearly elliptic, c. 2.1 by 0.8 mm, glabrous outside, rough and scurfy inside; disc lobes as staminate flowers; ovary 1 – 1.5 mm diam, densely pubescent; styles indiscernible; stigmas completely bifid, each arm c. 1 mm long, thickened at base, slender and often bent upward. Fruits c. 1 cm diam, appressed pubescent; sepals persistent but not accrescent; wall c. 0.5 mm thick, exocarp partly detaching; columella c. 6.5 mm long. Seeds 4.2 – 5.5 mm diam, pale brown when dry, hilum heart-shaped or rhombic, c. 1.2 by 1 – 1.2 mm. Distribution — Sumatra (endemic). Habitat & Ecology — Flowering and fruiting: September. Note — A distinct species with short petiole, inflorescences of short glomerules along an erect rachis and 5 stamens in the staminate flowers. Ridley (1925) described T. beccari and T. longisepalus as separate species but he did admit that these two species were possibly based on two sexes of one plant. Our recent collection R. Y. Yu 169 (L), from the Bogor Botanical Gardens (XI. B. XVII. 270 - 270 a, originally from Sumatra), bears both the same staminate and pistillate structures as described in Ridley (1925), and thereby confirms the conspecific status of T. beccari and T. longisepalus.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF74B7350FC86F80DFD8D9B28.taxon	distribution	Distribution — Borneo (Sarawak, endemic). Habitat & Ecology — On limestone. Altitude: recorded once from 80 m. Flowering: July. Note — The descriptions of the pistillate flowers and fruits are based on Milne (1995 a). This species is only known from the type collection from Sarawak. The species has the same characteristics of T. villosus var. merrillianus (e. g., long petiole, glomerules on inflorescences), but has 5 instead of 3 stamens. Since the number of stamens is generally reliably constant per species, this taxon is here regarded as a distinct species rather than a variety as it is in Milne (1995 a).	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF74D7350FFDCFEBFFA489F28.taxon	description	Shrubs or small trees, 1 – 8 m tall; flowering branches 1.7 – 3.2 mm diam. Bark 0.1 – 0.2 mm thick, brownish to greyish, slightly pubescent near young parts, smooth; wood pale yellowish. Stipules subulate, 0.5 – 1 mm long, caducous, pubescent at base. Leaves: petiole 0.3 – 1 (– 2.5) cm long, grooved above, pubescent; blade oblanceolate, oblong or obovate, 9 – 20 by 3 – 7 cm, chartaceous, base acute to obtuse, with 2 adaxial glands, margin distantly serrate, teeth small, falcate, apex acuminate, upper side glabrous, lower side paler, slightly pubescent and more or less ciliate along margin; midrib slightly raised on both sides, nerves 9 – 12 pairs, connected along margin, small veins reticulate. Inflorescences: staminate ones thyrsoid, branched (paniculate), 4 – 8 cm long, glabrescent, axillary or cauliflorous; bracts leaf-like, elliptic to oblong, up to 10 by 4 mm, slightly pubescent abaxially; pistillate inflorescences cymose, peduncles slender, 1 – 15 cm long, 0.2 – 0.5 mm diam, often only one flower at top (sometimes with few depauperate flowers below); bracts as in staminate inflorescences, 4 – 20 by 1 – 5 mm. Staminate flowers c. 6 mm diam; pedicel 0.2 – 0.4 cm long, 0.1 (middle part) – 0.2 (top) mm thick, glabrescent or Map 4 Distribution of Trigonostemon capillipes (Hook. f.) Airy Shaw (●); T. detritiferus R. I. Milne (★); T. flavidus Gagnep. (■). slightly pubescent; sepals elliptic, c. 1.6 by 1.2 mm, pale green, apex rounded or slightly notched, under the notch often with a gland on outside surface, but sometimes faint or only a few expanded cells; petals elliptic or spathulate, 3 – 3.5 by 1.5 – 1.8 mm, base narrowed, acute to cuneate, sometimes claw-like, entire, apex rounded, dark purple, in mature flowers with an orange flame-like honey mark in the middle of the lower part, smooth and glabrous outside, rough and papillose inside; disc lobes almost obtrapezoid, c. 0.35 by 0.3 mm, c. 0.1 mm thick, apex thickened and slightly reflexed, glabrous; stamens 5, androphore c. 0.6 mm long, c. 0.2 mm diam, 5 - branched at c. 0.1 mm below apex, filaments c. 0.1 mm long, anthers c. 0.7 mm long, pinkish, divaricate, connectives apically with numerous dark reddish droplets (or expanded cells) with secretion. Pistillate flowers c. 1 cm diam, pedicel slightly thickening towards apex, 6 – 9 mm long, apically c. 0.7 mm diam when flowering, in fruit accrescent to 1.5 cm long and apically c. 2 mm diam, slightly pubescent; sepals oblong to lanceolate, c. 4 by 2 mm when flowering, accrescent to 5 – 15 by 2 – 6 mm in fruit, pale green, margin slightly serrate, teeth glandular, apex acute to acuminate; petals as staminate flowers but larger, c. 5 by 2 mm; disc lobes rectangular, c. 0.4 by 0.6, apex truncate, corners rounded; ovary c. 1 mm diam, densely hairy, style c. 0.1 mm long, often indistinct, stigmas nearly completely divided, c. 0.9 – 1 mm long, free arms c. 0.8 mm long, slightly thickened abaxially. Fruits c. 1.2 cm diam, finely hairy; sepals and stigmas persistent, stigmas flattened at base, abaxially hairy; wall c. 0.4 mm thick, exocarp not detaching; columella c. 5 mm. Seeds c. 6 mm diam; hilum heart-shaped, 1 – 1.6 by 1.4 – 1.5 mm. Distribution — Thailand, Malay Peninsula. Habitat & Ecology — Lowland rainforest to mangrove forest. Altitude: 0 – 300 m. Flowering: December to April; fruiting: December to February. Note — Airy Shaw (1967) transferred this species from Dimorphocalyx to Trigonostemon without any information on staminate flowers in the type collection. Nevertheless, it can be recognized by the often single-flowered pistillate inflorescences and much enlarged sepals in pistillate flowers, and it differs from the newly proposed Philippine species T. victoriae by having thyrsoid staminate inflorescences and 5 instead of 3 stamens.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF74D7351FC85FA43FB7298E2.taxon	distribution	Distribution — Borneo (Temburong District of Brunei, endemic). Habitat & Ecology — Primary mixed dipterocarp forest, near rivers (c. 30 – 300 m away from river bank). Flowering and fruiting: June to November. Notes — 1. The species strongly resembles T. wetriifolius in the growing habit, cauliflorous flowers and adventitious roots, while the distinct differences lie in the dark reddish (vs pale yellowish in T. wetriifolius) petals and 3 (vs 5 in T. wetriifolius) stamens. 2. This species has a special living strategy (also seen in T. wetriifolius, see Airy Shaw & Ng 1978). The leaves are always clustered on the top of the main branch, where the adventitious roots also generate, thus the leaves accumulate dirt and fallen leaves from inside and form humus, from which the nutrition can be absorbed by the adventitious roots.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF74E7353FFDCFF67FD709E88.taxon	description	Trigonostemon diffusus Merr. (1928) 525; Jabl. (1963) 164; R. I. Milne (1995 a) 27, in key, 29, in key, 46. — Type: MjÖberg 145 (BM, K, UC *), Sarawak, Mount Poi. Shrubs or small trees, at least up to 6 m tall; flowering branches terete, 2 – 2.5 mm diam. Outer bark c. 0.1 mm thick, pale, slightly hirsute in young parts, glabrous and wrinkled in older parts; inner bark c. 0.2 mm thick, reddish brown; wood pale yellowish. Stipules falcate, 0.6 – 1 mm long, pubescent. Leaves: petiole 1 – 9 cm long, slightly pubescent, grooved above, thickened at base and top; blade oblong, 12 – 19 by 3.5 – 5.5 cm, membranous, sometimes slightly asymmetric, base acute and often with 2 adaxial glands, margin distantly crenate-dentate, teeth somewhat nipple-like, apex acuminate to caudate, surfaces olive-green, glabrous above and slightly hirsute beneath; midrib raised on both sides, slightly hirsute beneath, nerves 10 – 12 pairs, veins reticulate. Inflorescences paniculate, large and diffuse, much developed and branched but few flowers present, up to 35 cm long, slightly hirsute; bracts triangular, up to 0.6 by 0.3 mm, abaxial surface slightly pubescent. Staminate flowers (unopened) caducous, c. 1.7 mm diam; pedicel 2 – 3 mm long, 0.1 – 0.2 mm diam, glabrescent; sepals elliptic to ovate, 0.9 – 1.2 by 0.8 – 1 mm, slightly pubescent outside; petals elliptic, c. 1.5 by 1 mm, dark red or purple, margin slightly ciliate, apex rounded, both sides glabrous; disc lobes almost trapezoid, c. 0.2 by 0.3 mm; stamens 3, androphore c. 0.5 mm long, anthers ellipsoid, c. 0.6 mm long, connectives apically with numerous droplets with secretion. Pistillate flowers and fruits unknown. Distribution — Borneo (Sarawak, endemic). Habitat & Ecology — Forests near the foot of mountains. Altitude: 760 m. Flowering: September. Notes — 1. The species is only known from two collections (the type and J. W. Purseglove P. 4702). It is mainly distinguished by its large, diffuse, few-flowered inflorescences. 2. Trigonostemon diffusus subsp. condensus, should be synonymised under T. polyanthus, see note 3 under T. polyanthus.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF74E7353FFDCFADBFA3098C1.taxon	distribution	Distribution — Sumatra (endemic). Note — This species is characterized by the glomerules subtended by 2 large, leaf-like bracts. Detailed locality of the type collection, Korthals ‘ 853 ’, is based on Airy Shaw (1966).	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF74E7353FC86FD14FC569206.taxon	description	Trigonostemon filiformis Quisumb. (1930) 328, f. 7. — Type: M. S. Clemens 16751 (holo PNH †; iso A, NY *, UC *), Philippines, Luzon, Isabela Prov., Mt Moises. Small trees; flowering branches 1.5 – 3.5 mm diam. Outer bark c. 0.1 mm thick, brownish to greyish, smooth, pubescent in young parts; inner bark c. 0.1 mm thick, reddish, sap light red; wood yellow or white. Stipules small, subulate, 0.5 – 1 mm long, pubescent. Leaves: petiole 1 – 3 (– 4.5) cm long, 0.6 – 1 mm diam, terete, sometimes angled, or furrowed above, pubescent; blade linear to long lanceolate, 13 – 22 by 0.8 – 1.5 cm, chartaceous, base acute to cuneate, with 2 adaxial, falcate glands, margin distantly serrate, teeth glandular, apex acuminate to caudate, upper surface dark green, glabrous, lower surface paler, softly appressed pubescent; midrib plain above and slightly raised and densely pubescent beneath, nerves obscure, 10 – 13 pairs, curved to almost right angled, connected, pubescent beneath, veins reticulate, very vague. Inflorescences terminal or axillary, racemes or thyrses (but often only 1 flower developed on each node); rachis slender, 2 – 6 (– 13) cm long, 0.15 – 0.4 mm diam, pubescent; bracts lanceolate or oblong, 2 – 10 by 0.3 – 1.3 mm, slightly pubescent. Staminate flowers: sepals obovate to round, c. 1.5 by 0.5 mm; petals c. 2 by 1.25 mm diam; disc unknown; stamens 3, anthers sessile, erect, globose. Pistillate flowers 3.5 (unopen) – 7.5 (post-anthesis) mm diam; pedicels slightly thickened towards apex, 6 – 9 mm long, apically 0.8 – 1.1 mm diam, pubescent; sepals elliptic, 2.3 – 3 by 0.8 – 1.2 mm, accrescent to at least 9 by 2.2 mm, pubescent outside; petals oblong to oblanceolate, c. 4 by 1.25 – 1.5 mm, purple, glabrous; disc unknown; ovary at least 0.7 mm diam, densely pubescent; styles often indistinct, trifid; stigmas deeply bifid into 2 arms, each arm 0.6 – 1.2 mm long. Fruits and seeds unknown. Distribution — Borneo (Sabah) and Philippines (Luzon). Habitat & Ecology — Lowland forest edge, ultramafic soil in Sabah. Flowering: April and December. Notes — 1. The staminate flowers are not seen by us. The description is based on Quisumbing (1930). 2. The species is distinct from T. verticillatus var. salicifolius by the staminate flowers with 3 instead of 5 stamens. Another useful character is that T. verticillatus var. salicifolius often has two pairs of adaxial glands at leaf base, whereas T. filiformis always has one. 3. The type was collected from Mt Moises of the Philippines, as was the type of T. stenophyllus Quisumb. Both these two species are poorly known and probably they are conspecific, but this cannot be confirmed until further material is available of both species.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF751734CFFDCFF67FDD89D3F.taxon	description	Trigonostemon flavidus Gagnep. (1922) 749; (1925 b) 320; P. T. Li & M. G. Gilbert (2008) 273. — Type: Harmand 3273 (holo P), Laos, in Lakhon mountains, near Me-Kong. Trigonostemon heterophyllus Merr. (1930) 38; H. S. Kiu (1996) 163; Chantar. (2005) 24; (2007) 577, pl. 31: 1. — Type: W. T. Tsang 594 (= LU (Lingnan University) 17343) (A *, B *, BM, BO, ECON *, G *, K, L, MO *, NTUF *, NY *, P, PE, US, WIS *), China, Hainan, Danzhou County (Taam Chau District), Mt Sha Bao (Sha Po Shan). Evergreen, small trees, 1 – 2.5 m tall; flowering branches up to 4 mm diam, grey, densely hirsute. Bark c. 0.3 mm thick, smooth or roughened; wood reddish brown. Stipules subulate, c. 0.7 mm long, hirsute around base. Leaves: petiole terete but sometimes flattened or grooved above, 0.2 – 1.2 cm long, densely hirsute; blade obovate or oblanceolate, sometimes unequal, unevenly narrowed in the lower middle part, 9 – 35 by 5 – 9 cm, thin chartaceous or membranous, base abruptly rounded, with 2 adaxial glands, margin distantly serrate, teeth small and nipple-like, apex caudate to acuminate, dark green above and dull light green underneath, hirsute on both sides, especially on nerves and margin; midrib thin, elevated on both sides, nerves 10 – 12 pairs, veins reticulate, often obscure. Inflorescences bisexual, cauline, usually in short cymes or thyrses, 1 – 3 cm long, hirsute, often bracteate under nodes or flowers; bracts lanceolate to linear, up to 4 by 0.6 mm. Staminate flowers c. 6 mm diam; pedicel c. 3.5 mm long, c. 0.2 mm thick, pinkish, glabrous; sepals elliptic or obovate, c. 2 by 1 mm, base connate, margin ciliate, apex acute, hirsute outside, glabrous inside; petals obovate, 4 – 4.5 by 2 – 2.5 mm, base claw-like, apex rounded, glabrous, dark reddish to maroon-purple; disc glands elliptic or obovate, c. 0.5 by 0.25 mm, narrowed at base and slightly reflected at apex, light orange, glabrous; stamens 3, androphore c. 1 mm long, c. 0.1 mm diam, shortly trifid at top, filaments c. 0.2 mm long; anthers free, divaricate at top, each theca 0.4 – 0.5 mm long, connective with apically numerous droplets with secretion. Pistillate flowers few, slightly enlarged when fruiting, up to c. 1 cm diam; pedicel (in fruiting flower) c. 7 mm long, thickened towards apex to up to 1 mm diam; sepals long lanceolate to linear, c. 2.5 by 1.2 mm when flowering, accrescent to up to 7.5 by 2 mm in fruit, margin with a few teeth, apex acuminate, outside hirsute, inside glabrous; petals not seen, fallen; disc glands rectangular to semi-orbicular, c. 0.5 by 0.4 mm, rounded or truncate at apex, glabrous; ovary c. 3.5 mm diam, bright dark green, densely hirsute, styles almost indistinct, stigmas 3, completely divided. Fruits c. 1.2 mm diam, green, densely hirsute; wall woody, c. 5 mm thick; columella c. 5 mm long. Seeds c. 6.5 by 5.5 mm, dark brownish when dry, hilum irregularly shaped, more or less triangular, c. 1.5 mm diam. Distribution — India, China, Laos, Thailand, Malay Peninsula. Habitat & Ecology — Understorey in evergreen forest to deciduous hardwood or bamboo forest, often near rivers, growing on sandstone to conglomerate bedrock. Altitude: c. 200 m. Flowering: January to March; fruiting: February, July to October. Note — Trigonostemon flavidus is tentatively treated as a separate species here, but it strongly resembles T. semperflorens from India, of which it might be a synonym. It differs by having more hairs on the upper leaf surfaces.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF751734CFFDCF846FC7D9FC3.taxon	distribution	Distribution — New Guinea (Morobe district, endemic). Habitat & Ecology — Rainforest, growing on slope. Altitude: 150 m. Flowering and fruiting: January. Note — Descriptions of the staminate inflorescences, staminate flowers and ovary are based on Airy Shaw (1979). Only known from the type, Hartley 12211 (K, paratype) and a doubtful collections (Hartley 9811, K). The species is different from T. apetalogyne only by having 5 instead of 3 stamens (see also note under latter).	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF751734EFC85FA13FB989B2A.taxon	description	Trigonostemon anomalus Merr. (1920) 569; (1923) 451. — Type: FB (Villamil) 22018 (holo PNH †; iso A, US), Philippines, Mindanao, Zamboanga District, Naganaga. Trigonostemon laevigatus Müll. Arg. var. petiolaris Airy Shaw (1978) 417; R. I. Milne (1995 a) 28, in key, 29, in key. — Type: S (Chai) 19224 (holo K; iso L, SAN, SING), Sarawak, Fourth Division, Simpang Tiga, Ulu Mayeng, Kakus. Trigonostemon sp. nov., aff. chinensis Merr.: Jabl. (1963) 168. — Voucher: KEP (Strugnell) 20275 (K, KEP, SING), Malaya, Pahang, Ulu Gali Raub. See note. Trigonostemon sp. nov., aff. chinensis Merr.: Jabl. (1963) 168. — Voucher: van Steenis 910 (BO, L, SING), Sumatra, Anambas Islands, Siantan Island, E of Terimpa. See note. Trees, 5 – 15 m tall, stem up to 15 cm diam; flowering branches 1.5 – 2 mm diam, often slightly pubescent near nodes and apical buds. Bark 0.3 – 0.5 mm thick, smooth, lenticellate, light greenish to pale or dark brownish to blackish; sap red, pink or colourless; wood whitish to reddish brown, with brownish pink rays. Stipules falcate to nipple-like, 0.3 – 1 mm long, pubescent, caducous, often obscure or not seen. Leaves: petiole terete but often flat or grooved above, 0.5 – 1.5 (– 4) cm long, wrinkled, glabrescent to pubescent, base and apex sometimes pulvinate; blade elliptic, sometimes oblong, ovate or oblanceolate, 6 – 20 by 2.5 – 8 cm, chartaceous or coriaceous, base acute to cuneate, with 2 adaxial glands, margin entire, apex acuminate to caudate, above greenish, underneath pale green below, both sides glabrous; venation triplinerved, midrib elevated beneath, nerves 6 – 9 pairs, bow-shaped, narrowed along margin, veinlets reticulate, obscure. Inflorescences terminal or axillary, cymes or paniculate thyrses, abbreviated and condensed or elongated and lax, 0.5 – 4 cm long, often branched, glabrescent or pubescent, bracts long-triangular to linear, up to 3 by 1 mm, velutinous. Staminate flowers 6 – 10 mm diam; pedicel c. 1 cm long, c. 0.2 mm thick, scarcely pubescent; sepals oblong to obovate to orbicular, 2 – 4.5 by 1.8 – 2.5 mm, sometimes unequal, then outer 2 or 3 larger, imbricate, margin entire, apex rounded, yellowish green, often finely puberulent on both sides, outside also pubescent with longer hairs and sometimes with a subapical gland (var. croceus); petals flabellate and bilobed, each lobe 3 – 6 by 1.5 – 3 mm, yellow or reddish, glabrous, few parallel veins visible, base claw-like, apex notched to 1 / 3 to 1 / 2 of length and often with a small gland below the notch; disc annular, c. 0.5 mm high, glabrous, apex recurved; stamens 3, androphore 0.3 – 1.5 mm high, trifid at apex, filaments 0.2 – 0.5 mm long, anthers oblong, c. 0.8 mm long, yellow, free, base somewhat auriculate, not divaricate at apex. Pistillate flowers c. 6 mm diam, pedicel thickened towards apex, up to 2.5 cm long, apically c. 1 mm thick, slightly pubescent; sepals, petals and disc as in staminate flowers; ovary c. 1 mm diam, greenish, glabrescent to densely hairy, style c. 0.1 mm long, sometimes indistinct, stigmas 3 separate arms, c. 0.6 mm long, c. 0.1 mm thick, apex very slightly thickened and bifid. Fruits c. 1 cm diam, greenish, finely hairy; wall 0.4 – 0.6 mm thick, exocarp detaching; columella 5 – 6.5 mm long. Seeds 7 – 8 by 6 – 7 mm; hilum 1.5 – 3 by 1 – 2 mm. Distribution — Vietnam, Thailand, Malay Peninsula, Sumatra, Java, Borneo, Philippines, Lesser Sunda Islands. Map 5 Distribution of Trigonostemon laevigatus Müll. Arg. var. laevigatus (●) and T. laevigatus var. croceus (B. C. Stone) R. Y. Yu & Welzen (★). Note — The species is wide-spread and is often recognized by its short petiole, hairy sepals, and often flabellate and bilobed petals. The last three synonyms are only tentatively treated here because of the inadequate material.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF753734EFC86FBC1FB4E9C2B.taxon	distribution	Distribution — Thailand, Malay Peninsula. Habitat & Ecology — Hill evergreen forest to grassy sites. Altitude: 900 – 1300 m. Flowering: November to May. Note — Stone (1980) newly described T. croceus, because it had 5 instead of the 3 stamens of T. laevigatus. We dissected one staminate flower from the isotype and it turned out to have 3 stamens. Its only difference from the typical T. laevigatus are the showy, protruding glands on the sepals, but there is a continuous variation from being glandless to having a flat gland to even having a protruding gland. However, according to the specimen notes the croceus form occurs at higher altitudes than the typical laevigatus form. Therefore, T. croceus is here regarded as a variety of T. laevigatus.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7537348FC86F9BAFB8B98D5.taxon	description	Prosartema gaudichaudii Gagnep. (1925 a) 468, non Trigonostemon gaudichaudii (Baill.) Müll. Arg. (1865) 213. — Trigonostemon gagnepainianus Airy Shaw (1978) 415. — Syntypes: Gaudichaud 167 (P *), Vietnam, Tourane; Poilane 8306 (P *), Vietnam, from Nhatrang to Ninh Hoa; 10220 (P *), Vietnam, prov. de Quang Tri, Mai-lanh; Poilane 10446 (P *, K), Vietnam, Prov. de Quang Tri, Dent du Tigre.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7537348FC86F9BAFB8B98D5.taxon	description	Small trees, 1 – 5 m tall, stem up to 7 cm diam; flowering branches 2 – 5 (– 7) cm diam. Outer bark 0.1 – 0.25 mm thick, smooth, pubescent to hispid when young, whitish to brownish; inner bark 0.2 – 0.4 mm thick, yellowish to reddish brown, soft; sapwood 0.8 – 1.5 mm thick, white to dark brownish; heartwood 2 – 3 mm diam. Stipules linear to hook-like, 2 – 8.5 by 0.3 – 1 mm, often pubescent. Leaves: petiole terete, 0.4 – 3.5 cm long, often wrinkled, hispid; blade oblanceolate, (10 –) 12 – 28 (– 46) by (2.8 –) 4 – 10 (– 15) cm, membranous to chartaceous to coriaceous, base cuneate to round, margin distantly serrate, apex acuminate to slightly caudate, upper side glabrous to slightly pubescent, lower side often pubescent to hispid; midrib robust, elevated on both sides, nerves (9 –) 11 – 16 (– 33) pairs, often slightly curved and connected along margin, veins scalariform, veinlets reticulate. Inflorescences uni- or bisexual, axillary or terminal, loose or condensed, per node a single flower or short cymes, rachis (7 –) 15 – 30 (– 55) cm long, 0.5 – 4 mm diam, pubescent; bracts lanceolate to linear, 3 – 8 by 0.3 – 1 mm, pubescent. Staminate flowers 4 – 5 mm diam; pedicel 1.5 (Thailand, Malay Peninsula, Sumatra) – 5 (Borneo) mm long, 0.1 – 0.2 mm diam, pubescent, base articulate; sepals elliptic, 1.2 – 2 by 0.7 – 1 mm, green, margin entire, apex rounded, pubescent outside, glabrous inside; petals spathulate to obovate, 2 – 2.5 by 1.2 – 1.7 mm, pinkish to bluish black, base slightly claw-like, sometimes with 2 gland lobes (Thailand, Malay Peninsula, Sumatra), margin entire, apex rounded, smooth outside, often rough and papillose inside; disc annular, 0.2 – 0.4 mm wide, margin often 5 - notched; stamens 3, androphore c. 0.4 mm long, trifid at top, anthers free, divaricate, connective sometimes protruding at top (Thailand, Malay Peninsula, Sumatra). Pistillate flowers 4 – 5 mm diam; pedicel slightly thickened towards apex, 1.7 – 3 (Thailand, Malay Peninsula, Sumatra) – 9 (Borneo) mm long, apically 0.5 – 1 mm diam; sepals elliptic to lanceolate, 1.2 – 1.8 by 0.8 – 1.5 mm, margin entire, apex rounded to acute, pubescent outside, glabrous inside; petals and disc as staminate flowers; ovary c. 0.7 mm diam, densely pubescent, glabrescent, slightly (Thailand, Malay Peninsula, Sumatra, Borneo, Philippines) to extremely (Borneo) warty; styles short, often indistinct, trifid; stigmas bifid into 2 flattened lobes. Fruits 1.2 – 1.4 cm diam, green, pubescent, glabrescent, slightly to extremely warty; sepals persistent, not accrescent; wall 0.4 – 0.6 mm thick, exocarp partly splitting off; columella 5.5 – 6 mm long. Seeds 6.5 – 7 by 6 – 6.5 mm; hilum elliptic to rhombic to heart-shaped, 2 – 4.5 by 2.5 – 4 mm. Distribution — China, India, Thailand, Vietnam, Malay Peninsula, Sumatra, Borneo, Philippines. Habitat & Ecology — Primary to logged forests, flat land to hill sides, sometimes near rivers, growing on black soil or sandy or stoney clay. Altitude: 15 – 1000 m. Flowering and fruiting: all year round. Notes — 1. The staminate flowers are cauliflorous on one specimen (Wenzel 1513, BM). 2. Most of the species in this complex, now synonymised, were based on slight differences, but all show the same essential similarities including the short petiole, spike-like inflorescences and the more or less warty fruits. All of these indicate that they are conspecific. Two kinds of forms can be distinguished, though there is overlap via intermediates that cannot be placed: a form, often identified as T. elmeri, mostly distributed in Thailand, Malay Peninsula, Sumatra and parts of Borneo with short pedicel (1.5 – 3 mm long), petals with 2 glands at base and densely hairy but slightly warty fruits; another form, often identified as T. ionthocarpus, mainly in parts of Borneo and the Philippines with longer but thinner pedicel (3 – 9 mm long), petals with papillate hairs inside but without a basal gland and sometime extremely warty fruits. A molecular phylogeny of this species complex may enlighten an infraspecific distinction between the forms.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF755734AFC86FD21FEBB9B99.taxon	description	Trigonostemon longipes (Merr.) Merr. (1916 b) 191; Pax & K. Hoffm. (1919) 41; Merr. (1923) 452; Airy Shaw (1983 b) 47. — Dimorphocalyx longipes Merr. (1906) 82. — Lectotype (designated here): FB (Whitford) 1066 (lecto K; iso P), Philippines, Luzon, Bataan Prov., Mount Mariveles. Syntypes: FB (Borden) 1801 (BM, BO, K), Philippines, Luzon, Bataan Prov., Mount Mariveles; FB (Merrill) 2699 (BM, K), Philippines, Luzon, Province of Rizal, Bosoboso. Small trees, up to 4 m tall, stem c. 9 cm diam; flowering branches terete, 2 – 3 mm diam, glabrous except pubescent near apical buds. Bark c. 0.2 mm thick, pale brownish, smooth, wrinkled; wood pale yellowish. Stipules subulate, 0.5 – 1 mm long, pubescent. Leaves: petiole terete but grooved above, 1 – 8 cm long, glabrescent or slightly pubescent; blade oblong, sometimes oblanceolate, 5.5 – 16 by 2.5 – 6 cm, coriaceous, base cuneate, with 2 adaxial glands, margin entire or slightly crenate, apex acuminate to somewhat caudate, upper side dark green, lower side light green, both sides glabrous; midrib flat above and elevated underneath, nerves 8 – 11 pairs, curved and connected along margin, veinlets reticulate, often obscure. Inflorescences often unisexual, axillary or terminal, sometimes cauliflorous, thyrsoid, up to 15 cm long, glabrous or slightly pubescent, part of staminate flowers single and cauliflorous; few glomerules on a long main rachis, each node subtended by 1 bract; latter lanceolate, up to 1.5 by 0.8 mm, often pubescent; glomerules Map 7 Distribution of Trigonostemon longipes (Merr.) Merr. (★); T. lychnos (R. I. Milne) R. Y. Yu & Welzen (▲); T. magnificus R. I. Milne (■ including also ●); T. malaccanus Müll. Arg. (●); T. merrillii Elmer (▼). few-flowered (often 5 – 10 in staminate inflorescences and 1 – 3 in pistillate ones), bracteate under each flower, lanceolate, up to c. 0.7 by 0.5 mm, densely pubescent. Staminate flowers c. 4 mm diam; pedicel c. 1 mm long, c. 0.45 mm diam, slightly pubescent; sepals orbicular, c. 2 by 2 mm, imbricate, base connate, apex rounded, pubescent outside; petals elliptic, c. 2 by 1 mm, contort, margin sometimes ciliate; disc lobes obovate or semi-orbicular, c. 0.5 by 0.5 mm, c. 0.15 mm thick, glabrous, apex acute; stamens 5, androphore short, often indistinct, anthers c. 0.5 mm long, gathered on the top of androphore. Pistillate flowers c. 6 mm diam; pedicel 2 – 3 mm long, thickened towards apex, c. 1.2 mm thick; sepals oblong, slightly accrescent in fruit, up to 3.5 by 2 mm, pubescent outside, apex rounded; petals not seen, caducous; disc lobes semi-orbicular, c. 0.5 by 1 mm, glabrous; ovary not seen. Fruits c. 1 cm diam, glabrous; wall c. 0.4 mm thick; columella c. 3 mm long. Seeds c. 6 mm diam. Distribution — Philippines (endemic). Habitat & Ecology — Secondary forest, on clay loam. Altitude: 175 – 250 m. Flowering: January to April, September; fruiting: January, April. Note — The altitude information is based on Merrill (1906). The ovary is probably glabrous because the fruits are glabrous. The species strongly resembles T. verticillatus var. verticillatus in the variable long petiole and the 5 stamens of the staminate flowers, but they are different in their inflorescences: several flowers (often more than 5) cluster into significant glomerules along the main rachis and the internodes are relatively distinct in T. longipes whereas in T. verticillatus var. verticillatus flowers are evenly spread along the spike-like rachis (only 1 – 3 flowers present per node) and the internodes are very short. A molecular phylogeny may result in a better conclusion about its distinctiveness.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF757734AFFDCFDEDFF789DC0.taxon	distribution	Distribution — Borneo (Belait and Tutong districts of Brunei, endemic). Habitat & Ecology — Mixed lowland forest; heath forest on sandy soil (Milne 1995 a). Altitude: 50 m. Flowering: April. Vernacular — Sagubang Kayu (Brunei). Note — A distinct species with only a few collections. We regard it as a separate species because of its big difference from T. polyanthus in the variable petiole and blade and the showy subtending bracts under the inflorescences. The variable petiole and leaf-like bracts also resemble T. villosus var. merrillianus.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF757734AFFDCF812FCF59C48.taxon	distribution	Distribution — Sumatra (endemic). Habitat & Ecology — Recently logged-over or marshy forests. Flowering and fruiting: August. Note — A distinct but very rare species, known from two collections, the type and W. J. J. O. de Wilde & B. E. E. de WildeDuyfjes 19280, characterized by the tomentose indumentum, large and spreading inflorescences and sepals hairy on the inside.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7577344FC86F9A1FD73982D.taxon	distribution	Distribution — Thailand, Malay Peninsula, Sumatra. Habitat & Ecology — Evergreen forests to recently logged-over forests on hill ridges or in valleys, sometimes near rivers. Altitude: 100 – 850 m. Flowering: all year round; fruiting: June to August, November to February. Vernacular name — Malay Peninsula: Putat. Notes — 1. Trigonostemon malaccanus resembles T. heteranthus but has stubby staminate pedicels (often shorter than 2 mm, wider than 0.3 mm diam) rather than the slim pedicels of T. heteranthus (often longer than 2 mm and c. 0.1 mm diam), and entire pistillate sepals (vs fimbriate in T. heteranthus). 2. Trigonostemon malaccanus is also similar to T. verticillatus var. verticillatus but differs by having 5 instead of 3 stamens and the young inflorescences with distinct short and stiff hairs.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7597344FFDCFDB9FF339229.taxon	distribution	Distribution — Philippines (endemic). Habitat & Ecology — Lowland dipterocarp forest. Altitude: 15 m. Flowering: March. Note — The species resembles T. oblongifolius in the male inflorescences but differs from the latter by the blade being hairy on both sides. The description of fruits is based on Elmer (1911).	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7597345FC86FF67FD679B71.taxon	description	Trigonostemon oblongifolius Merr. (1912) 409; Pax & K. Hoffm. (1914) 407; Merr. (1923) 452; Airy Shaw (1983 b) 47. — Type: BS (Ramos) 13965 (holo PNH †; iso A, US), Philippines, Luzon, Prov. Cagayan, Abulug River. Trigonostemon luzoniensis Merr. (1920) 568; (1923) 452; Airy Shaw (1983 b) 47. — Type: PNH (Ramos & Edaño) 33539 (holo PNH †; iso A, K), Philippines, Luzon, Camarines Prov., Paracale. Small trees, up to 6 m tall; flowering branches terete, 2 – 4.5 mm diam, whitish and sparsely pubescent when young, buds densely golden pubescent. Bark c. 0.2 mm thick, smooth, pale brownish. Stipules subulate or falcate, 0.5 – 1 mm long, caducous, pubescent near base. Leaves: petiole terete but often grooved above, 0.5 – 3.5 cm long, more or less hirsute; blade oblong, 4 – 23 by 2 – 6.5 cm, coriaceous, base acute or rounded, margin often slightly recurved, apex acute, upper side paler (when dry), glabrous above and sparsely pubescent beneath; midrib often elevated and hirsute beneath, nerves 6 – 12 pairs, curved and often connected along margin, veinlets almost indistinct. Inflorescences: staminate ones (pre-flowered) paniculate thyrses, often axillary, at most few branched and with short glomerate cymes along the main rachis and the lateral branches, main rachis up to 18 cm long, 0.5 – 1 mm thick, slightly pubescent, bracteate under each branch, bracts lanceolate, c. 2 by 0.6 mm, hirsute outside; secondary branches often short, 0.5 – 1.5 cm long, cymes scorpioids, clustered, paintbrush- or broom-like, few-flowered, each flower bracteate; the latter lanceolate, up to 0.8 by 0.5 mm, hairy outside; pistillate ones (post-flowered, infructescences) racemose, axillary, c. 5 cm long, glabrescent; bracts lanceolate, c. 1.5 by 0.7 mm, glabrous. Staminate flowers (unopened) c. 1.5 mm diam; pedicel c. 1 mm long, glabrous; sepals orbicular to ovate, c. 1.4 by 1.3 mm, imbricate, slightly hairy outside; petals ovate, c. 0.5 by 0.5 mm, glabrous; disc indistinct; stamens 3, androphore short, hidden, anthers gathered into a head on the top of androphore, c. 0.3 mm long. Pistillate flowers (fruiting): pedicel 2 – 2.2 cm long, thickened towards apex and scarcely hairy, sepals elliptic, c. 1.2 by 0.8 mm, outside sparsely pubescent near base; ovary villous; stigmas apically cleft, the lobes c. 0.5 mm long. Fruits c. 1 cm diam, appressed-hirsute, warty; wall c. 0.6 mm thick, exocarp partly splitting off; columella c. 5.5 mm long. Seeds c. 6 by 6.5 mm, dark brown; hilum heart-shaped, 2.5 – 3 by 1.5 – 1.8 mm. Distribution — Philippines (Luzon, endemic). Habitat & Ecology — Flowering: January. Map 8 Distribution of Trigonostemon oblongifolius Merr. (▼); T. pentandrus Pax & K. Hoffm. (▲); T. polyanthus Merr. (■); T. rufescens Jabl. (●); T. sandakanensis Jabl. (★). Note — The description of the ovary is based on Merrill (1912). The species has similar-looking inflorescences as T. polyanthus, but the main rachis is more distinct and the secondary rachis is much shorter and condensed than those of the latter species.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7587347FFDCFEFEFAD19B55.taxon	description	Trigonostemon pentandrus Pax & K. Hoffm. (1914) 406; Jabl. (1963) 164. — Type: Hubert Winkler 1792 (not traced), Malaya, Gunung Angsi near Sungei Gadub. Neotype (designated here): KEP FRI (R. Y. Yu) 86653 (holo L; iso KEP), Malaysia, Negeri Sembilan, Gunung Angsi. Small trees, 1 – 2.5 m tall; flowering branches 5 – 7 mm diam, pith sometimes of loose tissue. Outer bark 0.2 – 0.25 mm thick, pale greyish, slightly fissured, glabrous; inner bark 0.15 – 0.4 mm thick, dark reddish to brownish, fibrous, sap orange; wood 0.5 – 0.6 mm diam, whitish to yellowish. Stipules subulate to nipple-like, 0.5 – 1 mm long, glabrous. Leaves: petiole terete, 3.5 – 8 cm long, 2 – 3.2 mm diam, glabrous, thickened at base and apex, base somewhat sheathing; blade oblong, 23 – 35 by 6 – 9.5 cm, coriaceous, base cuneate, with 2 adaxial glands, nipple-like, showy, margin distantly serrate, teeth short-subulate, thickened, apex acuminate to caudate, upper side dark green, lower side pale green, both sides glabrous; venation penninerved, glabrous, midrib robust, slightly raised above and distinctly elevated beneath, nerves 14 – 16 pairs, straight, narrowed and branched and connected along margin, veinlets reticulate, often obscure. Inflorescences bisexual, (sub) terminal, short racemose, rigid, staminate flowers at top, pistillate flowers below, 2 – 6.5 cm long, rachis 1.3 – 2 mm diam, densely hirsutulous. Staminate flowers 6 – 7 mm diam; pedicel 2 – 3 mm long, 0.4 – 0.5 mm diam, pinkish red, hispidulous; sepals elliptic, 1.3 – 2 by 1 – 1.5 mm, white, base connate, margin entire or slightly irregularly undulate, ciliate, apex acute to rounded to emarginate, hirsutulous outside, glabrous inside; petals obovate, 3 – 4.2 by 2.5 – 3.2 mm, pink, base narrowed and somewhat claw-like, margin often wrinkled, apex bilobed, glabrous on both sides; disc lobes glandular, 0.6 – 0.7 by 0.3 – 0.6 mm, c. 0.15 mm thick, glabrous; stamens 5, androphore erect, 0.7 – 1 mm long, 0.2 – 0.3 mm diam near base, slightly narrowed above, 5 - cleft at apex; anthers ellipsoid, 0.9 – 1 mm long, free, divaricate, connectives apically often with numerous dark reddish droplets (expanded cells) with secretion. Pistillate flowers c. 0.3 mm diam (petals fallen); pedicel c. 1.7 mm long, articulated at base, c. 0.5 mm diam when flowering, slightly elongating in fruit to 3.5 – 4.5 mm long and c. 1.5 mm diam, hirsutulous; sepals elliptic to triangular, 2 – 2.8 by 1 – 1.2 mm, margin entire, ciliate, apex rounded to acute to acuminate, hirsutulous outside, glabrous inside; petals not seen, fallen; disc as staminate flowers; ovary c. 1.2 mm diam, reddish, densely hispid; styles indistinct; stigmas deeply fibid into 2 arms of 1.2 – 1.5 mm length, thickened at apex. Fruits c. 5.5 mm diam, red in living plants, brownish when dry, densely hispid, sepals (slightly accrescent) and stigmas persistent; wall 0.4 – 0.5 mm thick, exocarp less than 0.1 mm thick, not detaching; columella c. 5 mm long. Seeds not seen. Distribution — Malay Peninsula (Gunung Angsi, endemic). Habitat & Ecology — Flowering and fruiting: September to December. Notes — 1. The species resembles T. verticillatus but a few unusual or unique characters make the species quite distinct: thicker leaves, one pair of showy blackish adaxial glands on leaves (glands not showy, but sometimes can be two pairs in T. verticillatus), shorter inflorescences and pinkish instead of reddish purple flowers. 2. The species has remained inadequately known and was only mentioned once (Jablonski 1963) since the original publication. The original type collection (Hubert Winkler 1792) is not seen by us and is presumably lost, but our field observations and collections from Gunung Angsi (type locality) match the original description by Pax & Hoffman (1914) very well. We are strongly convinced that this is a good and distinct species. For more specimen citations, see Identification List.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF75A7340FC86FEA1FA9F9F00.taxon	description	Trees or treelets, 6 – 15 (– 20) m tall, dbh 6 – 25 (– 40) cm, flowering branches up to 6.5 mm thick, brownish, glabrescent, slightly scaberulous basally. Outer bark hard, 0.5 – 1 mm thick, brownish to greyish, rugose, lenticellate; inner bark 2 – 5 mm thick, pinkish to reddish, brownish (when dry); exudate clear, pinkish; wood dirty pinkish white. Stipules falcate, sometimes linear, up to 1.5 – 2 by c. 0.4 mm, pubescent near base, caducous. Leaves: petiole terete, 1.5 – 15 cm long, 0.8 – 2.5 mm diam, glabrous or slightly pubescent, base in apical leaves often somewhat sheathing; blade elliptic to sometimes obovate, 10 – 31 by 4 – 13.5 cm, coriaceous, base acute or cuneate, with 2 adaxial falcate glands, margin distantly serrate to crenate, teeth subulate or falcate, apex acuminate to caudate, sometimes acute, dark green above, pale green beneath, both sides glabrous or with a few very scattered hairs; venation often slightly pubescent, midrib slightly raised above and raised beneath, nerves 8 – 14 pairs, curved, branched and connected along margin, veins and veinlets reticulate, obscure. Inflorescences often terminal, paniculate, much branched and many-flowered, up to 30 cm long (up to 15 cm long in the Philippines), usually unisexual to bisexual, finely pubescent; bracteate under each node, bracts triangular, 0.5 – 2.5 (– 5) by 0.2 – 1 mm (larger ones basal in inflorescence, smaller ones higher up; often longer in Thai and Vietnamese specimens), outside pubescent, inside glabrous, on large branches sometimes caducous and often with 2 falcate or subulate bracteoles at the sides (Sumatra and Borneo), up to 1 mm long. Staminate flowers c. 5 mm diam; pedicel 3.5 – 4 mm long, c. 0.2 mm thick, pubescent, articulate at base; sepals elliptic or somewhat obovate, 1.2 – 1.6 by 0.6 – 0.8 mm, pale greenish or greenish yellow, base narrowed and connate, margin somewhat translucent, apex rounded or slightly undulate, outside pubescent, often with a gland in the middle, inside glabrous; petals obovate to spathulate, 2.5 – 4 by 1.2 – 2 mm, base cuneate to claw-like, entire, apex rounded, yellowish, sometime pale cream inside and with a paler margin (Philippines), midrib and few parallel veins visible, glabrous; disc lobes trapezoid, 0.2 – 0.3 by 0.2 – 0.3 mm, c. 0.1 mm thick, fleshy, apex thickened, reflexed; stamens 3, androphore c. 0.5 mm long, free terminal part sometimes slightly trifid at top, sometimes bent (Sumatra and Borneo), anthers splitting off subapically from androphore, ellipsoid, c. 0.2 mm long, cream, divaricate (mainly in specimens from Thailand and Vietnam), connectives apically with droplets with secretion. Pistillate flowers of same size as staminate ones; pedicel 2.5 – 3.5 mm long, apex slightly thickened, 0.6 – 0.7 mm thick; sepals and petals as in staminate flowers; disc lobes rectangular, c. 0.4 by 0.6 mm, apex truncate; ovary c. 1 mm diam, glabrous and warty, styles extremely short, stigmas with a shallow groove above. Infructescence pendulous, dull pale light green. Fruits c. 1.5 cm diam, greenish, glabrous, warty or aculeate above; pedicel 2.5 – 4 cm long, green; sepals persistent but not accrescent; wall woody, c. 0.6 mm thick, exocarp partly detaching; columella c. 0.8 cm long. Seeds 6 – 7.5 mm diam, dark brown when dry; hilum long-triangular to heart-shaped, 1 – 2.5 by 0.5 – 1.2 mm. Distribution — Thailand, Vietnam, Malay Peninsula, Sumatra, Borneo, Philippines. Habitat & Ecology — Lowland evergreen to deciduous forests, sometimes on limestone hills, near rivers; growing on red to yellow calcareous soils to granite bedrocks. Flowering and fruiting: all year round. Notes — 1. The inflorescences are mainly unisexual because they generally consist of flowers of the same gender but sometimes are mixed with a few flowers of the other sex. The flowers can spread evenly along secondary rachis, whereby the whole panicle attains a pyramid-shape (Thailand and Vietnam), or the flowers cluster in brush- or broom-like groups on tertiary branches and the inflorescences seem more umbellate (Sumatra and Borneo). 2. Many collections (in many herbaria) of this species are incorrectly identified either as T. sumatranus or T. paniculatus (or ‘ T. paniculatum ’) for a historical reason. Pax & Hoffman’s (1911) T. sumatranus was based on Forbes 2647 (BM, K, L), and is actually a synonym of T. viridissimus, a species that also bears paniculate inflorescences but can be easily distinguished from T. philippinensis by its much shorter petioles and stigmas being almost not bifid.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF75D7342FC86FA54FD7398C8.taxon	description	Trigonostemon polyanthu s Merr. (1914) 492; (1923) 452; Airy Shaw (1983 b) 48. — Type: BS (Ramos) 1645 (holo PNH †; iso BM, BO, BRI *, G *, GH *, L, NY *, P *, SING), Philippines, Samar, Cauayan Valley.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF75D7342FC86FA54FD7398C8.taxon	distribution	Distribution — Philippines (Samar and Luzon). Habitat & Ecology — Flowering: April to June. Notes — 1. A distinct species with paintbrush-like staminate inflorescences. Only 2 specimens present, the type specimen from Samar and PHN (M. Lagrimas et al.) 39433 from Luzon. 2. Milne (1995 a) wrongly cited PNH (Ramos) 42686 as type of T. polyanthus (but later corrected this in an erratum via a printed sheet among the specimens), as it is not the type and actually belongs to T. villosus. Therefore, the reference of Milne (1995 a) is not listed under T. polyanthus. 3. The holotype for T. diffusus subsp. condensus cited by Milne (1995 a), PHN (M. Lagrimas et al.) 39437, might be a misprint as it should be PHN (M. Lagrimas et al.) 39433 (same date and place as 39437). He also cited BS (Ramos) 1645 as a paratype, but he probably did not notice that it was the type of an older name – T. polyanthus. Although T. diffusus shares some similarity with T. polyanthus in the inflorescences, the differences are also striking and necessitate that both species are kept distinct, e. g., the inflorescences of T. diffusus are more elongated, diffuse and paniculate with a relative clear main rachis in the middle (PNH (M. Lagrimas et al.) 56725) and much longer internodes, and the pedicels are glabrous and thinner. Both species are relatively rare, more collections are desired.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF75F7342FFDCFD1FFC399B0A.taxon	description	Trigonostemon rufescens Jabl. (1963) 152, f. 2; Whitmore (1973) 135. — Type: SFN (Corner) 29428 (holo SING; iso A *, BO, K, L, SAN, SING), Malaysia, Johore, 13.5 miles on Mawai – Jemaluang Road. Small trees, up to 3 m tall; flowering branches 4 – 6 mm diam. Indumentum of densely golden hispid hairs. Outer bark c. 0.1 mm thick, dark brownish, hispid; inner bark c. 0.1 mm thick, blackish, sap red; sapwood 0.85 – 1 mm thick, whitish to pale yellowish; heartwood 2.6 – 2.8 mm diam, pale brownish, often hollow. Stipules subulate, c. 1 mm long, densely hispid, caducous. Leaves: petiole subterete, more or less furrowed above, 2 – 13 cm long, hispid; blade oblong to oblanceolate, 18 – 32 by 5 – 12 cm, coriaceous, base cuneate, acute to rounded or narrowly cordate, 2 adaxial glands often present, margin very distantly serrate, teeth subulate, apex acuminate to aristate, densely golden hispid on both sides; midrib flat above and elevated beneath, with two layers of hairs, soft pilose and hispid, nerves 11 – 14 pairs, curved and narrowed near margin, veins reticulate, often obscure above and distinct beneath. Inflorescences: staminate ones racemes or glomerules, 2 – 9 cm long, hispid; bracts lanceolate or linear, 8 – 20 by 1 – 5 mm, hispid; pistillate inflorescences racemose, up to 6 cm long, axillary, few-flowered (often only the top one develops), hispid; bracts as staminate ones. Staminate flowers c. 6 mm diam; pedicel at least 3.5 mm long, c. 0.4 mm diam, sparsely hirsutulous; sepals oblong, at least 3 by 1.2 mm, villose outside, glabrous inside; petals obovate or oblong, 3.5 – 5.5 by 1.5 – 2.2 mm, dark reddish, both sides glabrous; disc lobes elliptic, c. 0.4 by 0.4 mm, apex acute, glabrous; stamens 5, androphore erect, c. 1.5 mm long, 5 - cleft at top, filament 0.3 – 0.4 mm long, anthers free, divaricate at top into two lobes, each lobe 0.65 – 0.8 mm long. Pistillate flowers c. 1.2 cm diam; pedicel c. 6.5 mm long, c. 0.7 mm diam, hispid; sepals lanceolate, 5.5 – 6.6 by 1.5 – 2.5 mm, apex acuminate, densely hispid outside, sparsely hispid inside; petals elliptic, c. 4.5 by 2 mm, margin wrinkled and irregular, apex near acute, glabrous on both sides; disc lobes rectangular to semi-orbicular, c. 0.4 by 0.8 mm, glabrous; ovary c. 1.3 mm diam, glabrous, evenly narrowed at top, styles c. 0.3 mm long, stigmas c. 1 mm long, bifid to middle. Fruits (immature) c. 7 mm diam, pinkish, pedicel c. 1 cm long, c. 2 mm diam (top); persistent sepals triangular, 1.2 – 1.5 by 0.6 mm. Seeds not seen. Distribution — Malay Peninsula (Mawai – Jemaluang Road, endemic). Habitat & Ecology — In drier part of swamps and on dry hill rocks. Flowering: February, May. Notes — 1. This is a densely hairy species but the ovary turns out to be completely glabrous in our dissection, which is different from Jablonski’s (1963) original description. 2. It is only known from its type locality where most of the forests have been replaced by oil palm plantations and the species, resampled in 2016 by the first author, is now extremely threatened.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF75F7342FC85FE5AFB7D9DAF.taxon	distribution	Distribution — Borneo (Sabah, endemic). Habitat & Ecology — Primary forest, near stream. Altitude: 5 – 20 m. Flowering: April to June; fruiting: December. Note — A unique species only known from the Kabili-Sepilok Forest Reserve in Sandakan, Sabah. The petals are linear and the inner surface is very rough and scurfy.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF75E737CFFDCF951FB779B85.taxon	description	This species resembles T. villosus, but there are two kinds of inflorescences, those on the leafless parts are contracted and those in the axils of still present leaves are elongated and have the flowers especially in the upper part and may resemble brooms, the ovary is glabrous. — Type: KEP FRI (P. F. Cockburn) 7859 (holo L; iso K, KEP, SING), Malaysia, Johore, Ulu Endau, Labis FR, Compt. 277. Paratypes: KEP FRI (F. S. P. Ng) 5207 (KEP, L), Malaysia, Johore, Mersing, Arong FR, Compt. 90; Joseph Lai & Ali Ibrahim LJ 22 (SING), Singapore, Mandai Forest, next to Mandai Columbarium; Joseph Lai & Ali Ibrahim LJ 80 (SING), Singapore, Mandai, Central Catch- ment Nature Reserve. Small trees, up to 3 m tall; flowering branches c. 3.5 mm diam, sometimes hollow. Outer bark 0.1 – 0.2 mm thick, dark brownish, tomentellous; inner bark 0.1 – 0.3 mm thick, dark reddish to blackish; sapwood 1.5 – 2 mm thick, brown; heartwood c. 1.5 mm diam, brown. Stipules subulate, c. 0.5 mm long, often covered with hairs. Leaves: petiole terete, 2.5 – 12 cm long, hispidulous; blade oblong, 12 – 26 by 4 – 7.5 cm, chartaceous, base narrowly cordate, glands not seen, margin entire or slightly, distantly serrate, apex acuminate, upper side dark brownish to black (when dry), glabrous, lower side brown (when dry), papillate-hispid; venation penninerved, papillose hispid on lower side, midrib flat above and elevated beneath, nerves 10 – 13 pairs, straight or slightly curved, branched and connected along margin, veins scalariform, veinlets reticulate. Inflorescences bisexual, in the leafless parts fascicled, in the axils of still present leaves elongated and racemose or thyrsoid, with the flowers concentrated at the upper part of the rachis and broom-like, rachis up to 10 cm long, 0.8 – 1 mm diam, densely hispid; bracts lanceolate, 4 – 5 by 0.6 – 1.2 mm, apex acuminate, densely hispid outside, glabrous inside. Staminate flowers 2.5 – 3.5 mm diam; pedicel 4.5 – 5.5 mm long, 0.2 – 0.3 mm diam, hispidulous; sepals lanceolate to linear, 1 – 1.5 by 0.2 – 0.3 mm, margin entire or slightly serrate, apex acuminate, outer surface hispid and with few whitish oil-like spots; petals elliptic, 1.2 – 1.5 by 0.7 – 0.8 mm, dark red to purple, glabrous on both sides; disc lobes rectangular to obtrapezoid, c. 0.2 by 0.2 mm, apex truncate, often slightly revolute; stamens 3, androphore c. 0.4 mm long; anthers gathered on the top of androphore, ellipsoid, c. 0.5 mm long. Pistillate flowers 0.45 – 0.5 mm diam; pedicel 6 – 8 mm long, 0.4 – 0.5 mm diam, densely hispid; sepals lanceolate, 2.5 – 3 by c. 0.5 mm, margin entire, apex acuminate, hispid outside, glabrous inside; petals elliptic, 2.4 – 3 by 1 – 1.5 mm, dark red, margin entire, base and apex acute, glabrous outside, rough and slightly papillate inside; disc obtrapezoid, c. 0.45 by 0.45 mm, apex truncate; ovary c. 0.8 mm diam, glabrous; styles short, sometimes indistinct, c. 0.1 mm long; stigmas deeply bifid, arms 0.6 – 0.7 mm long, bent, thickened abaxially and sagittate near base. Fruits and seeds unknown. Distribution — Malay Peninsula (endemic, only found in Johor, Malaysia and Singapore). Habitat & Ecology — Disturbed forest near logging road; moist gully. Altitude: low. Flowering: March.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF760737DFFC3FF64FB849B06.taxon	description	Map 10 Distribution of Trigonostemon scopulatus R. Y. Yu & Welzen (◆); T. serratus Blume (▼); T. sinclairii Jabl. (●); T. victoriae R. Y. Yu & Welzen (■); T. wetriifolius Airy Shaw & Ng (★); T. wildeorum R. Y. Yu & Welzen (▲). Distribution — Java (endemic). Habitat & Ecology — Rainforest. Flowering: November. Note — The young branches are reddish (in dried specimens) and pubescent. The outer bark regularly sheds off, and reddish stripes remain. In older parts the branches become pale greyish or brownish.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF760737DFC86FE4EFC69923A.taxon	description	Trigonostemon sinclairii Jabl. (1963) 154, f. 3, 4; Whitmore (1973) 135. — Type: SFN (Sinclair & Kiah bin Salleh) 40418 (holo SING), Malaya, Terengganu, Block 3 B Gunong Tebu F. R., 51 st mile Kuala Terengganu – Berut Road. Shrubs or small trees, up to 5 m tall, stem sparsely branched, flowering branches 0.8 – 1.3 mm diam. Indumentum often of 2 layers of simple hairs, shortly villose and longer papillate-hispid. Outer bark 0.1 – 0.2 mm thick, often fissured, yellowish to brownish, villose and papillate-hispid; inner bark c. 0.5 mm thick, fibrous, dark brownish to blackish, with sap; sapwood 0.2 – 0.3 mm thick, yellowish to reddish brown; heartwood 0.4 – 0.7 mm diam, brownish. Stipules subulate, c. 1 mm long, caducous, often not seen. Leaves: petiole 4 – 15 cm long, villose and hispid; blade oblong, 20 – 45 by 8 – 17 cm, coriaceous, base obtuse or slightly cordate, with 2 adaxial glands, latter falcate or subulate, but often covered by long hairs, margin entire, often papilloseciliate, apex acute to acuminate, or sometime rounded, both sides papillate-hispid; midrib raised and densely villose and hispid on both sides, nerves 15 – 20 pairs, slightly raised on both sides, curved and narrowed near margin, with two layers of hairs, villose and papillate-hispid, veins scalariform, papillate-hispid (only one layer, not villose), veinlets reticulate, obscure above. Inflorescences: staminate ones axillary, raceme-like thyrses, rachis up to 25 cm long, densely villose but sparsely hispid; bracts linear, 6 – 12 by 0.7 – 1 mm, hispid; pistillate inflorescences axillary, racemose, or sometimes sparsely branched at bottom, rachis sometimes hollow, up to 40 cm long, villose and hispid; bracts as staminate inflorescences, but larger, up to 20 by 2 mm. Staminate flowers c. 7 mm diam; pedicel 0.5 – 0.8 mm long, 0.2 – 0.4 mm diam, sparsely hispid; sepals lanceolate, 1.5 – 2 by 1 – 1.5 mm, apex acute, outside hispid and with a gland near apex, inside glabrous, sometimes with a few pale pustules on both sides; petals elliptic, c. 4.8 by 2.5 mm, base rounded, apex acute to rounded, dark reddish, contort, glabrous to often with sparsely pale pustules on both sides; disc glands rhomboid, 0.5 – 0.7 by 0.4 – 0.65 mm and c. 0.2 mm thick, apex acute, occasionally with sparsely pale pustules; stamens 3, androphore erect, c. 0.6 mm long, anthers ellipsoid, gathered on the top of androphore, 0.5 – 0.6 mm long, connectives with numerous apical pustules or droplets with secretion. Pistillate flowers (fruiting) 1 – 2 cm diam; pedicel 1 – 1.2 cm long, c. 1 mm diam, villose and sparsely hispid; sepals triangular, already enlarging, c. 2 by 1 cm, finally leaf-like, persistent, margin with few teeth near top, apex acuminate, both sides hispid and often villose or ciliate along veins and margins; petals not seen, caducous; disc lobes semi-orbicular, c. 0.4 by 0.7 mm; ovary densely hispid, styles c. 0.5 mm long, stigmas completely bifid, arms c. 0.8 mm long, bent. Fruits c. 1.5 cm diam, hispid outside; wall c. 0.6 mm thick, exocarp not splitting off; columella c. 6.5 mm long. Seeds c. 6.5 mm diam, often with sparse pustules on surface; hilum elliptic, c. 4 by 2 mm, apex often apiculate. Distribution — Malay Peninsula (endemic). Habitat & Ecology — Primary forest to newly logged forest on hill side. Flowering: May and August; fruiting: July and September. Note — An extremely hairy species with large accrescent pistillate sepals.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF763737EFFDCFF67FA499E36.taxon	description	Small trees, up to 8 m tall; flowering branches terete, 2.5 – 3 mm diam. Bark 0.4 – 0.5 mm thick, pale greyish; wood pale yellowish. Stipules subulate, 0.5 – 1.5 mm long, blackish and pubescent near base, yellowish at apex. Leaves: petiole wrinkled, terete but grooved above, 2 – 9 cm long, often thickened at apex and base; blade oblong, sometimes elliptic or lanceolate, occasionally linear, 10 – 22 by (1.5 –) 2.5 – 5 cm, chartaceous or coriaceous, base acute to rounded, 1 or 2 pairs of glands adaxially present, subulate or falcate, often glabrous, margin distantly serrate, teeth subulate, apex acuminate to caudate, upper surface dark green, lower surface pale green, both sides glabrous; midrib slightly raised above and distinctly elevated beneath, nerves 12 – 21 pairs, connected along margin, veinlets reticulate, often obscure. Inflorescences bisexual, terminal or subterminal, racemes (spike-like) or thyrses, often puberulent, main rachis up to 10 cm long, involucral bracts triangular to lanceolate to falcate, 1 – 2 by c. 0.5 mm, with 2 lateral bracteoles; bracts to flowers broadly triangular, somewhat sheathing, up to 1 by 1 mm, apex acuminate, puberulent. Staminate flowers c. 4 mm diam (unopened); pedicel slightly thickened towards apex, 1.5 – 3 mm long, apically 0.6 – 0.8 mm diam, glabrous or very slightly puberulent; sepals often unequal, orbicular to ovate, 1 – 1.5 by 1 – 1.5 mm, imbricate, apex rounded, outside glabrous or slightly puberulent, margin ciliate; petals ovate, 2.5 – 2.8 by c. 2 mm, dark reddish, contort, apex rounded, outer surface glabrous, inner surface rough and slightly papillose, margin entire, occasionally slightly ciliate; disc annular when young and cupular when mature, c. 0.5 mm wide, margin often with 5 notches; stamens 5, androphore c. 0.5 mm long, anthers ellipsoid, c. 1 mm long, divaricate, connectives apically with numerous droplets (or expanded cells) with secretion. Pistillate flowers c. 5 mm diam; pedicel as staminate flowers but longer and thicker, c. 4 mm long, c. 1 mm diam; sepals elliptic, c. 1.5 by 1 mm when flowering, more or less accrescent to 3 by 2 mm when fruiting, apex rounded, outside slightly puberulent, margin ciliate; petals as staminate flowers, caducous; disc annular, subentire; ovary 1.2 – 1.5 mm diam, puberulent, style c. 0.2 mm long, sometimes indistinct, stigmas c. 0.7 mm long, bifid at apex, arms c. 0.5 mm long, thickened abaxially, reniform at base. Fruits c. 1 cm diam, outside finely puberulent; wall 0.7 – 1 mm thick, exocarp detaching. Seeds c. 5.5 mm diam; hilum rhombic, c. 1.8 by 1 mm. Distribution — Vietnam, Thailand, Malay Peninsula. Note — The genus Enchidium, described by Jack (1822), is reliably identical to Trigonostemon, even though there were a few mistakes in the manuscript, e. g., he mentioned that the plants have 10 stamens, instead of 5. The genus remained monospecific since Jack’s publication. Jack’s original collection from Sumatra was never checked again by later botanists and it is very likely that it does not exist anymore (Merrill 1952). The illustration Jack cited (see Rumphius 1743) is a sterile plant and does not appear to be Trigonostemon. Probably on account of the obscure status of Enchidium, botanists tended to abandon the name even though it was validly published prior to Trigonostemon. For example, Hooker (1887) regarded E. verticillatum as synonym under the later published T. indicus. Jackson (1893, 1895) reduced Enchidium as a synonym under Trigonostemon. Pax & Hoffmann (1911) also transferred the type species E. verticillatum to T. verticillatus and synonymised T. indicus under T. verticillatus. The genus was eventually rejected in 1954 (see Introduction). Because Jack’s collection is not available and illustration is incorrect, a neotype is here designated to T. verticillatus. We followed Pax & Hoffmann’s (1911) treatment and the neotype specimen is chosen from one of Pax & Hoffmann’s (1911) vouchers.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7637378FC86FA03FE569BFB.taxon	description	Leaves: blade nearly linear, 10 – 16 by 1.5 – 2.5 cm. Petals with a slightly ciliate margin. Distribution — Malay Peninsula (endemic). Habitat & Ecology — Dipterocarp forests. Altitude: 80 – 150 m. Flowering: January and July. Note — This is a tentative treatment, data from a molecular phylogeny is needed. The variety mainly differs from var. verticillatus by having narrower leaves.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7657378FFDCFE11FDA79238.taxon	description	This species resembles T. capillipes in the pistillate inflorescences and enlarged pistillate sepals, but differs by having racemose staminate inflorescences, staminate flowers with 3 stamens and pistillate flowers with sepals hairy inside and glabrous ovaries. — Type: PNH (Sulit) 12317 (holo L), Philippines, Palawan Province, Victoria Mountains, Panacan, Aborlan. Small trees, up to 6 m tall, dbh c. 10 cm; flowering branches 2 – 2.5 mm diam. Outer bark 0.1 – 0.2 mm thick, pale greyish, somewhat shiny, pubescent near apical buds and glabrescent in mature parts; inner bark 0.1 – 0.2 mm thick, dark reddish; wood pale yellowish. Stipules subulate, 0.5 – 1 mm long, often persistent, base pubescent, apex glabrous. Leaves: petiole terete but grooved above, 0.5 – 3 cm long, pubescent; blade elliptic, 6 – 11 by 2 – 4 cm, chartaceous to coriaceous, base acute to rounded, 2 adaxial glands present, often pubescent, margin distantly serrate, teeth glandular, apex acuminate to slightly caudate, upper side glabrous, dark red in dry specimens when young to pale grey and shiny when mature, lower side sparsely pubescent; venation penninerved, often pubescent on the lower side, especially in young leaves, midrib more or less raised above and elevated beneath, nerves 6 – 8 pairs, curved and narrowed along margin, veinlets reticulate. Inflorescences unisexual, racemose, staminate ones c. 5 cm long, c. 0.5 mm diam, appressed pubescent; bracts lanceolate to oblong, 1 – 3 by 0.3 – 0.6 mm, appressed pubescent; pistillate inflorescences often with only 1 flower at the top of inflorescences and sometimes a few depauperate buds below; peduncles up to 5 cm long, c. 0.5 mm diam, pubescent; bracts lanceolate to elliptic, 3 – 4 by 0.3 – 0.7 mm, pubescent. Staminate flowers (unopened) c. 3 mm diam; pedicel 0.5 – 1 mm long, c. 0.5 mm diam, pubescent; sepals ovate to elliptic, 1 – 1.5 by 0.8 – 1.1 mm, imbricate, margin entire, apex acute to acuminate, pubescent outside; petals orbicular, 0.9 – 1.1 mm diam, dark purplish, glabrous on both sides; disc lobes semi-orbicular, c. 0.2 by 0.1 mm, fleshy, apex acute; stamens 3, androphore indistinct, anthers ellipsoid, grouped at the top of androphore, c. 0.45 mm long. Pistillate flowers c. 4 mm diam; pedicel c. 3 mm long, c. 0.5 mm diam, sericeous; sepals lanceolate, 2.5 – 4 by 0.6 – 1.5 mm when flowering, accrescent to 10 – 13 by 2.5 – 4.5 mm when fruiting, margin with a few indistinct teeth, apex acute to acuminate, sericeous on both sides, denser outside; petals elliptic to ovate, 1.1 – 1.4 by 1 – 1.2 mm, glabrous except for ciliate margin; disc lobes rectangular, 0.15 – 0.2 by 0.2 – 0.25 mm, apex truncate, glabrous; ovary c. 0.65 mm diam, glabrous; styles c. 0.1 mm long, stigmas deeply divided and reniform, arms straight, c. 0.3 mm long. Fruits and seeds not seen. Distribution — Philippines (Victoria Mountains, endemic). Habitat & Ecology — Dipterocarp forests, growing on clay, near rivers. Flowering: May. Note — Only known from the type collection. The mature leaves often turn greyish and are shiny, but this could be a drying artefact. Another useful distinction is that T. victoriae only has a few small bracts along the pistillate inflorescences while its resembling species, T. capillipes, tends to have larger, leaf-like bracts under the pistillate flowers.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7657375FC86FF64FD709BCC.taxon	description	Trigonostemon carnosulus Airy Shaw (1978) 415. — Type: CF (Yeop) 844 (holo K), Malaya. Trigonostemon polyanthus auct. non Hook. f.: R. I. Milne (1995 a) 25. Small trees, up to 6 m tall, dbh up to 6 cm; flowering branches 2.5 – 6 mm diam, buds pubescent. Outer bark 0.1 – 0.3 mm thick, pale brownish to greyish, often pubescent when young, glabrescent lower, sometimes fissured; inner bark 0.1 – 0.3 mm thick, dark reddish; sapwood 0.6 – 1.4 mm thick, pale yellowish; heartwood 0.6 – 1 mm diam, brownish, soft. Stipules subulate, 0.8 – 1.8 mm long, pubescent. Leaves: petiole terete but often furrowed above, 0.5 – 25 cm long, glabrous to hirsute, sometimes slightly thickened at base and apex; blade elliptic to oblong (Malay Peninsula, Borneo, Philippines) or oblanceolate (Sumatra), 6.5 – 32 by 2.5 – 14 cm, chartaceous, base cuneate, acute, obtuse or rarely slightly cordate (East Kalimantan), 2 adaxial glands present, margin distantly serrate, teeth small, subulate or falcate, apex acuminate to caudate, Map 12 Distribution of Trigonostemon villosus Hook. f. var. borneensis (Merr.) Airy Shaw (★) and T. villosus var. merrillianus (Airy Shaw) R. Y. Yu & Welzen (●). Map 13 Distribution of Trigonostemon villosus Hook. f. var. villosus (◆) and T. villosus var. cordatus R. Y. Yu & Welzen (▲). upper side glabrous, dark green, lower side paler and to a different extent villose; midrib flat or slightly raised above and distinctly elevated beneath; nerves 7 – 12 (– 15) pairs, often bow-shaped, narrowed along margin, veins reticulate, sometimes obscure. Inflorescences unisexual or bisexual, racemes (pistillate ones if unisexual) or thryses, sometimes condensed, often axillary, sometimes cauliflorous, villose; rachis up to 42 cm long, 0.3 – 0.9 mm diam, staminate flowers clustered into short cymes or glomerules along rachis, pistillate flowers often single per node; bracts linear to lanceolate, 0.8 – 3.2 by 0.2 – 1.1 cm, margin entire (Borneo, Philippines) or serrate (Malay Peninsula, Sumatra), glabrous to villose, bracteoles (Malay Peninsula) lanceolate to linear, up to c. 5.5 by 1 mm, villose. Staminate flowers 3.5 – 6 mm diam, pedicel 2 – 3.5 mm long, 0.2 – 0.3 mm diam, pinkish (Sabah), glabrous; sepals elliptic, 2 – 2.5 by 1 – 1.4 mm, imbricate, white (Sabah), margin ciliate, apex rounded, outer surface slightly pubescent, sometimes with a very faint gland near apex, inner surface glabrous or rarely slightly villose (only one collection, van Balgooy 2187, Malay Peninsula); petals elliptic to obovate to spathulate, 2 – 3.8 by 1 – 2 mm, purplish black, base often with a pinkish flame-like honey mark inside (Borneo), margin entire, apex rounded, smooth and glabrous outside, rough and papillose inside; disc lobes rectangular or obtrapezoid, c. 0.5 by 0.5 mm, yellowish (Sabah), apex truncate, sometimes reflexed; stamens 3, androphore 0.4 – 0.9 mm long, anthers ellipsoid, 0.5 – 0.6 mm long, pinkish (Sabah), connectives apically with numerous reddish droplets with secretion. Pistillate flowers 6 – 8 mm diam, pedicel often slightly thickened towards apex, 3.5 – 10 mm long, apically 0.5 – 1.2 mm diam, green or red, glabrous to hairy; sepals lanceolate (Malay Peninsula, Sumatra) or elliptic to oblong (Borneo, Philippines), 2.5 – 6 by 0.8 – 1 mm when flowering, sometimes accrescent when fruiting, up to c. 9 by 2.3 mm, white in flowers, turning green in fruits (Sabah), margin serrate (teeth often glandular, Malay Peninsula, Sumatra) to entire (Borneo, Philippines), apex acuminate, outer surface sparsely to densely villose, sometimes with a faint abaxial gland near apex, inner surface glabrous, very occasionally villose (one collection from Malay Peninsula); petals as staminate flowers but larger and caducous, 3 – 5 by 1.5 – 2.3 mm; disc rectangular, 0.3 – 0.9 by 0.5 – 0.6 mm, membranous, apex rounded or truncate; ovary c. 1 mm diam, glabrous to densely villose, styles short, indistinct, stigmas 3, completely bifid, free arm 0.8 – 1.3 mm long. Fruits c. 0.9 – 1.2 cm diam, villose; wall 0.4 – 0.6 mm thick; columella 4 – 6 mm long. Seeds 5 – 6.5 by 4.5 – 6.5 mm, hilum heart-shaped, 1.8 – 3.2 by 1.4 – 2.4 mm. Distribution — Malay Peninsula, Sumatra, Borneo, Philippines. Notes — 1. Milne (1995 a) misinterpreted T. polyanthus because he cited a wrong type specimen. The actual T. polyanthus is a very distinct species, differing from T. villosus in its penicillate or fastigiate inflorescences. 2. This species consists of four varieties spreading over a huge area (Map 12, 13) of great morphological variation. We made this treatment based on a large number of collections showing that this massive variation actually connects all single forms together into a species complex, even though the ex- treme forms often do not resemble each other (see Fig. 18). These extremes, furthermore, have often become the source of synonyms, where the species status is only valid in the type locality, but in a larger area, intermediate forms are always found. As morphological discontinuities are the only valid argu- ment for species / variety delimitation, all the forms in Fig. 18 are regarded as a single species despite the wide distribution; and T. villosus var. cordatus is described as a separate variety, regardless of its small distribution area (Sabah). 3. Generally, the hairs on leaf surfaces, the size of petioles and leaf blades and the inflorescence structure can be good characters to tell the varieties apart. The varieties villosus and borneensis all have relatively stable and similar leaf blade and petiole sizes (Fig. 16), but they are different in inflorescence and flower structures – in var. borneensis, the inflorescences are unisexual (vs bisexual in var. villosus, but staminate flowers often fall off), the pistillate inflorescences have fewer flowers (often fewer than 4) at a time (vs often more than 4 in var. villosus), and the pistillate sepals are not much accrescent and often have an subapical gland outside (vs obviously accrescent and with a faint or no gland in var. villosus). The new variety cordatus has a hairy leaf blade, which forms a typical morphological discontinuity separating it from var. borneensis. The variety merrillianus is different from var. borneensis by its much (variable) longer petioles, much larger blades, often leaf-like bracts and staminate flowers in condensed glomerules.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7657375FC86FF64FD709BCC.taxon	description	2. Inflorescences bisexual. — Malay Peninsula ............................................ a. var. villosus 2. Inflorescences unisexual ......................... 3 3. Leaves glabrous above. — Sumatra, Sabah, Philippines) ................................ b. var. borneensis	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7687375FFDCFBDDFB7B9B55.taxon	distribution	Distribution — Sumatra, Borneo (Sabah), Philippines. Habitat & Ecology — Primary lowland rainforests, often on hillsides or near rivers, growing on well-drained brown loam soil. Flowering: June to December; fruiting: July to December. Note — Some collections from Sumatra (e. g., W. J. J. O de Wilde & B. E. E de Wilde - Duyfjes 19367, 21244, 21362) display an intermediate form between the variety villosus and variety borneensis. They have short petioles (shorter than 2.5 cm), seemingly unisexual inflorescences and often 1 or 2 pistillate flowers per inflorescence at one time, which all show clear allegiance to var. borneensis. Because of this, they are tentatively placed under var. borneensis even though there is a huge gap between their main distribution locations (Sumatra, Sabah), but the serrate sepals of the pistillate flowers with an acuminate apex do somewhat resemble var. villosus.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7687375FC86FEA1FBF89EAA.taxon	description	A variety found in Sabah resembling Trigonostemon villosus Hook. f. var. borneensis (Merr.) Airy Shaw but differs from the latter by the leaves often being cordate at base and pubescent on the upper surface. — Type: SAN (R. Y. Yu & Jemson) 158479 (holo L; iso SAN), Sabah, Sandakan, Kabili-Sepilok Forest Reserve. Paratypes: SAN (R. Y. Yu et al.) 158458 (L, SAN), Sabah, Tepid, Tawai Forest Reserve; SAN (R. Y. Yu et al.) 158459 (L, SAN), Sabah, Tepid, Tawai Forest Reserve; SAN (R. Y. Yu et al.) 158460 (L, SAN), Sabah, Tepid, Tawai Forest Reserve; SAN (R. Y. Yu & Jemson) 158480 (L, SAN), Sabah, Sandakan, Kabili-Sepilok Forest Reserve; SAN (R. Y. Yu & Jemson) 158481 (L, SAN), Sabah, Sandakan, Kabili-Sepilok Forest Reserve; Stone 6747 (KLU, L), Sabah, Sandakan, Kabili-Sepilok Forest Reserve; SAN (Asik Mantor) 113362 (SAN), Sabah, Ulu Sg. Mantuluk Witti Range area. Leaves: petiole 0.5 – 2.5 cm long; blade elliptic, 8.5 – 22 by 3.5 – 9.5 cm, often cordate at base, pubescent on both sides. Inflorescences unisexual, racemose or thyrsoid, 6 – 14 cm long, staminate flowers often cauliflorous, a few flowers per node along the rachis. Staminate flowers: sepals elliptic, white; petals claw-like, with a flame-like honey mark near the base. Pistillate flowers: sepals elliptic, green, apex rounded, margin entire, slightly accrescent in fruit; ovary glabrous to densely villose. Fruits green, pubescent. Distribution — Borneo (Sabah, endemic). Habitat & Ecology — Lowland rainforests, often on ultramafic soil. Flowering: December to March; fruiting: December. Note — This variety is sometimes misidentified as T. merrillii because of the hairy leave surfaces, but from its racemose or thyrsoid inflorescences (very few flowers per node, certainly not short paintbrush-like glomerules as in T. merrillii) it easily differs from the latter species.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF7687376FC86FB3DFE12987B.taxon	description	Trigonostemon laxiflorus Merr. (1920) 567; (1923) 451; Airy Shaw (1983 b) 47. — Type: BS (Ramos & Edaño) 31097 (holo PNH †; iso A *, K, P *, US *), Philippines. Leaves: petioles 1 – 25 cm long; blade ovate to elliptic, 8 – 32 by 2.5 – 14 cm, both sides often glabrous. Inflorescences unisexual, barely branched thyrses, up to 42 cm long, often with one large and leaf-like bract under each branch; staminate flowers often cauliflorous or in densely clustered glomerulus (Borneo) or cymes (Philippines) along a robust rachis; pistillate inflorescences racemose, robust and erect. Staminate flowers: sepals often with a faint to showy gland near the apex outside; petals sometimes with an orange to yellowish flame-like honey mark inside near the base. Pistillate flowers: sepals elliptic, entire to serrate, when serrate then teeth glandular; ovary often glabrous, occasionally slightly pubescent. Fruits pubescent. Distribution — Borneo, Philippines. Habitat & Ecology — Understorey in primary to burned or logged-over forests, sometimes on hill tops or slopes or along riversides, growing on red clay loam soil. Altitude: 50 – 900 m. Flowering: February to June, October to December; fruiting: September to May. Note — This variety has the most variable petioles and leaf blades and more condensed staminate flowers on inflorescences: the plants from the Philippines have relatively shorter petioles, smaller blades and less condensed staminate flowers on each inflorescence node, whereas the plants from East and West Kalimantan have longer petioles (up to 25 cm long) and larger blades; in Sarawak (type locality) and Brunei, the plants have the most condensed glomerules along the staminate inflorescences. For more details, see Fig. 18. In fact, this massive variation was also seen by Milne (1995 a) when he tried to synonymise T. acuminatus, T. borneensis and T. merrillianus under T. polyanthus, although T. villosus (not T. polyanthus) is the correct species name.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF76B7376FFDCFD8AFA369C01.taxon	description	Trigonostemon membranaceus Pax & K. Hoffm. (1911) 91. — Type: Koorders 32989 (BO), Java: Djapara.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF76B7376FFDCFD8AFA369C01.taxon	description	Neotrigonostemon diversifolius Pax & K. Hoffm. (1928) 385; (1931) 169. — Type: Parker 2593 (K), Burma, Mergui, Ngawun Reserve. Shrubs or small trees, up to 9 m tall, stem up to 10 cm diam; flowering branches 1.5 – 3 mm diam, sometimes hollow. Bark c. 0.3 mm thick, young parts pale and pubescent, sometimes with numerous oil-like spots, mature parts dark, brownish to greyish, glabrescent; wood pale yellowish. Stipules subulate to nipple-like, c. 0.5 mm long, caducous, often pubescent. Leaves: petiole terete but grooved above, 0.5 – 1.5 (– 5.5) cm long, wrinkled, pubescent; blade ovate to elliptic to oblong, sometimes lanceolate, 8 – 24 by 2.5 – 9 cm, membranous or chartaceous, often with numerous oil-like spots when young, Map 14 Distribution of Trigonostemon viridissimus (Kurz) Airy Shaw var. viridissimus (●) and T. viridissimus var. elegantissimus (Airy Shaw) Airy Shaw (★). base acute or obtuse, often with 1 or 2 pairs of adaxial glands, margin entire or slightly distantly serrate, apex acuminate to caudate, upper side glabrescent to glabrous, dark green, lower side often sparsely pubescent, paler and dull green; venations triplinerved, midrib and 2 basal nerves slightly raised above and well elevated beneath, often pubescent, especially near base, other nerves 6 – 10 pairs, bow-shaped and connected along margin, veins scalariform, veinlets reticulate. Inflorescences bisexual (but mostly unisexual), often axillary, loose paniculate, often with oil-like spots on young parts; main rachis terete, up to 25 cm long, c. 2 mm diam, slightly pubescent; branches slender and glabrescent; bracts lanceolate, up to 2 mm long, pubescent. Staminate flowers 5 – 9 mm diam; pedicel up to 9 mm long, c. 0.2 mm diam, glabrescent or slightly pubescent, often with numerous oil-like spots; sepals elliptic or orbicular, 1 – 1.5 by 0.6 – 1.2 mm, imbricate, margin somewhat undulate, apex rounded or truncate, often with a short notch, outer surface pubescent, often with numerous oil-like spots and a gland in the middle; petals obovate, 4 – 6.5 (– 10) by 3.5 – 4.5 (– 7) mm, contort, membranous, with several distinct parallel veins, base cuneate or somewhat claw-like, apex rounded, glabrous; disc annular, margin undulate, reflexed, sometimes with 5 notches; stamens 3, androphore 0.7 – 1.5 mm long, filaments 0.3 – 0.4 (– 0.6) mm long, anthers free, ellipsoid, 0.4 – 0.5 mm long. Pistillate flowers 5 – 9 mm diam, pedicel slightly thickened towards apex, 1 – 1.4 cm long, apically c. 0.5 mm diam when flowering, elongating up to 3 cm long and c. 1.4 mm diam in fruit, glabrescent, often with oil-like spots; sepals, petals and disc as staminate flowers, except petals caducous when fruiting; ovary 0.8 – 1 mm diam, glabrous, with numerous oil-like spots on surface, styles 0.2 – 0.6 mm long, stigmas 0.6 – 1.5 mm long, bent, slightly thickened and slightly bifid at apex. Fruits c. 1.5 cm diam, greenish, glabrous and with numerous oil-like spots, sepals persistent but not accrescent; wall c. 0.5 mm thick, exocarp detaching; columella c. 5 mm long. Seeds 7 – 8 mm diam, with numerous oil-like spots on surface; hilum rhombic, c. 1.5 by 1.2 mm. Distribution — China, India, Thailand, Laos, Vietnam, Malay Peninsula, Sumatra, Java, Borneo, Philippines, Lesser Sunda Islands. Habitat & Ecology — Primary to secondary forests, along coasts to hillsides, sometimes along rivers. Note — In addition to the Malesian region, this species is also found in China, India, Thailand, Laos and Vietnam under different names, all synonyms except viridissimus, which is the oldest and accepted epithet for this species.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF76A7377FFC3FF67FE3C9912.taxon	description	Leaves: petiole 1.5 – 5.5 cm long, glabrous to slightly pubescent; blade oblong to lanceolate, glabrous above, glabrous to sparsely pubescent beneath. Inflorescences often terminal or subterminal, erect and firm, glabrous. Distribution — Vietnam, Malay Peninsula, Borneo. Habitat & Ecology — Growing on sandy loam to sandy stone. Altitude: 170 – 230 m. Flowering: March to September; fruiting: July, October. Note — The form elegantissimus is here recognized as a variety, following Airy Shaw (1975). The two varieties closely resemble each other in their floral structures, like the contort petals, the slender long and only shortly bifid stigmas. The length of the petiole and the shape of the leaf blade also show some overlap. Milne (1995 a) presents a good discussion on the differences between the two varieties although he treated them as two separate species.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF76A7377FFC3FC65FAA79E78.taxon	distribution	Distribution — Malay Peninsula (Lesong Forest Reserve, endemic). Habitat & Ecology — Primary lowland forest under logging. Flowering: September. Note — Only known from the type specimen. Two slides of the plant (see Fig. 19, taken by Francis Ng) are attached with the type specimen. Descriptions of staminate flowers are mainly based on the slides, thus the measurements might not be exactly accurate, since a scale was unavailable; other parts of descriptions are based on Airy Shaw & Ng (1978). The species resembles T. detritiferus in morphology and living strategy, for more details, see notes under T. detritiferus.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF76A7371FC86FB8FFF319953.taxon	description	This species resembles T. aurantiacus, but differs in the flowers with the sepals covered by dense silky hairs and in the 5 (in stead of 3) stamens. — Type: W. J. J. O de Wilde & B. E. E. de Wilde - Duyfjes 20274 (holo L; iso BO), Indonesia, North Sumatra, Atjeh, Middle Alas River (Lae Sauraya) area, c. 15 km N of Gelombang, S of Bengkong River, N 2 ° 55 ' E 99 ° 57 '. Paratype: W. J. J. O de Wilde & B. E. E de Wilde - Duyfjes 18742 (BO, KLU, L, P), Indonesia, North Sumatra, Atjeh, southern part of the reserves, Alas River valley, near the mouth of the Bengkong River, c. 50 km S. of Kutacane, N 3 ° E 97 ° 50 '. Small trees, 2 – 4.5 m tall; flowering branches 1.5 – 3 mm diam, buds golden sericeous. Bark c. 0.3 mm thick, pale greyish, appressed sericeous to hirsutulous when young, often smooth and fissured when mature; sapwood c. 2 mm thick, brownish; heartwood c. 2 mm diam, whitish. Stipules subulate, 0.5 – 0.6 mm long. Leaves: petiole terete, 0.5 – 1 cm long, flat above, rounded beneath, appressed hirsutulous; blade obovate, 7.5 – 22 by 3.5 – 7.5 cm, chartaceous to coriaceous, base cuneate to acute, 2 adaxial glands present, these subulate to falcate, caducous, margin entire to distantly serrate, ciliate, teeth small and falcate, apex caudate, tip 0.8 – 2.5 cm long, sometimes slightly slanting, upper side dark brownish (when dry), sparsely sericeous when young, pale brownish to greyish (when dry), glabrescent when mature, lower side brownish, sparsely sericeous; venation penninerved, midrib flat above and elevated beneath, hirsutulous to sericeous on both sides, nerves 8 – 12 pairs, straight, branched and slightly curved along margin, often hirsutulous beneath, veinlets reticulate. Inflorescences reduced to a cauliflorous fascicle of at most 3 flowers; bracts oblong to linear, 1 – 2.5 by 0.3 – 0.5 mm, hirsutulous. Staminate flowers c. 6 mm diam; pedicel c. 0.5 mm long, 0.3 – 0.4 mm diam, densely hirsutulous; sepals elliptic, 1.5 – 2 by 0.8 – 1.3 mm, base connate, margin entire, apex acute to rounded, outside densely sericeous to hirsutulous, inside slightly floccose; petals obovate, c. 3.5 by 2.5 mm, dark purplish black, base slightly claw-like, entire, apex rounded, glabrous on both sides, few dark palmate veins often visible; disc lobes semi-orbicular, 0.4 – 0.5 by 0.6 – 0.8 mm, apex sometimes with a shallow notch; stamens 5, monadelphous, androphore erect, c. 1 cm long, c. 0.3 mm diam, anthers free, ellipsoid, divaricate, each theca c. 0.5 by 0.3 mm. Pistillate flowers c. 5 mm diam (not fully opened); pedicel c. 1 mm long, apically c. 1 mm diam, slightly thickened near apex, densely pubescent; sepals triangular, 3 – 3.5 by 1.5 – 2.5 mm, base narrowed and connate, margin serrate, apex acuminate, outside densely hirsutulous to sericeous, inside hirsutulous to pubescent, accrescent in fruits, then elliptic to ovate, up to 1.3 by 1 cm, base rounded to truncate, margin distantly serrate, apex acute, sometimes with a small notch, outside a few palmate veins visible, sericeous especially on veins, inside sparsely sericeous; petals ovate to elliptic, c. 2.5 by 1.5 – 2 mm, dark purplish black, caducous, margin entire, apex acute to acuminate, glabrous; disc lobes as staminate flowers; ovary c. 0.8 mm diam, densely pubescent, style indistinct, stigmas c. 0.9 mm long, deeply bifid, arms c. 0.7 mm long, thickened and slightly sagittate at base. Fruits c. 1 cm diam, puberulent outside; wall c. 0.5 mm thick, exocarp partly splitting off; columella c. 5 mm long. Seeds c. 6 mm diam. Distribution — Sumatra (endemic). Habitat & Ecology — Primary foothill forest on yellow-red loamy soil over basalt rock. Altitude: 50 – 200 m. Flowering and fruiting: July. Note — Only known from the two collections mentioned above.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF76C7371FFDCFC5AFEFA9256.taxon	description	Trigonostemon angustifolius Merr. (1922) 396. — Type: BS (Ramos & Edaño) 36764 (of 36560) (holo PNH †; iso A, K, US), Philippines, Mindanao, Zamboanga District, Malangas. Shrubs, 1 – 3 m tall; flowering branches c. 3 mm diam. Outer bark c. 0.1 mm thick, white to grey, smooth, slightly pubescent when young, glabrescent; inner bark 0.2 – 0.3 mm thick, dark brownish; wood white to yellow. Stipules very small, pointing, appressed pubescent, caducous. Leaves: petiole terete but grooved above, 5 – 8 mm long, 1.2 – 1.5 mm diam, appressed pubescent; blade oblong, 10 – 15 by 2 – 3 cm, chartaceous, base acute, glands not seen, margin distantly serrate, teeth glandular, apex acuminate to shortly caudate, upper surface dark brown to black (when dry), glabrous, lower surface reddish brown, slightly pubescent; midrib slightly raised and glabrous above, distinctly elevated and pubescent beneath, nerves 8 – 11 pairs, pubescent beneath, veins reticulate, obscure above. Inflorescences: staminate ones not seen; pistillate ones axillary, slender, peduncled, a glomerule at apex; peduncle c. 5 cm long, c. 0.5 mm diam, appressed pubescent; glomerules few-flowered, subtended by two bracts (also one bract present on the lower node), bracts lanceolate, 10 – 12 by 2 – 3 mm, appressed pubescent beneath. Staminate flowers not seen. Pistillate flowers: sepals lanceolate, c. 6 by 2.5 mm, apex acuminate, outside eglandular, slightly pubescent; petals 5 – 6 mm long, glabrous, dark purple; ovary glabrous, styles 3, stigmas cleft nearly to the base, arms linear, 1.5 mm long, acuminate. Fruits depressed globose, c. 12 mm diam, brown, sparingly appressed pubescent, sepals accrescent up to 12 by 6 mm. Seeds not seen. Distribution — Philippines (Mindanao, endemic). Habitat & Ecology — On forested slopes at low altitudes (Merrill 1922). Flowering: October. Vernacular name — Pululi (Merrill 1922). Note — The species is only known from the type collection. Due to the insufficient material seen the descriptions of pistillate flowers and fruits are based on Merrill (1922). Knowledge on the staminate flowers of the species is still lacking and, therefore, it is impossible to even determine whether the species belongs to Trigonostemon or not.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF76C7372FC86FF67FD73984A.taxon	description	Map 15 Distributions of Trigonostemon angustifolius Merr. (●); T. cumingii Müll. Arg. (★); T. stenophyllus Quisumb. (■); T. whiteanus (Croizat) Airy Shaw (▲). c. 9, arranged into 2 whorls, outer whorl 5, alternate with disc glands, opening introrse, free, filaments c. 0.15 mm long, inner whorl c. 4, opening more or less extrorse, connate into an androphore, hidden, c. 0.5 mm long, anthers ellipsoid, c. 0.6 mm long. Pistillate flowers, fruits and seeds unknown. Distribution — Philippines (endemic). Habitat & Ecology — Rugged country, on red clay soil. Altitude: 300 m. Flowering: June. Note — A rare and poorly known species. The stamens are arranged into two whorls with c. 5 free outer and 4 inner connate ones, which seems typical for Dimorphocalyx, but the inflorescences are too much condensed. A molecular phylogenetic study is necessary to determine this species affiliation.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF76F7372FFDCFD9FFF639C23.taxon	description	Trigonostemon stenophyllus Quisumb. (1930) 330, f. 8. — Type: BS (Ramos & Edaño) 47331 (holo PNH †; iso A, K, NY *, UC *), Philippines, Luzon, Isabela Prov., Mount Moises. Shrubs, up to 1 m tall; branches terete, 2 – 3.5 mm diam, pubescent when young, glabrous when mature. Stipules unknown. Leaves: petioles 1 – 4 cm long, somewhat pubescent; blade oblong to lanceolate, 5.5 – 16.5 by 1 – 2.5 cm, chartaceous, base acute to obtuse, margin entire to slightly distantly serrate, apex acuminate, upper surface brown to dark brown when dry, glabrous, lower surface paler and sparsely pubescent; midrib flat above and elevated beneath, nerves 6 – 11 pairs, veinlets reticulate. Inflorescences: staminate ones unknown; pistillate ones axillary, racemose, up to 5.5 cm long, pubescent; bracts narrowly lanceolate, 3 – 4 mm long. Staminate flowers unknown. Pistillate flowers c. 4.5 mm diam; pedicels slightly thickened towards apex, c. 9.5 mm long, apically c. 0.6 mm diam, appressed pubescent; sepals oblong to lanceolate, c. 3 by 0.7 mm, margin entire, apex acute to acuminate, appressed pubescent outside, glabrous inside; petals oblong-obovate, c. 5 by 2 mm, apex rounded, glabrous; disc lobes elliptic, c. 0.5 by 0.3 mm, apex rounded, glabrous; ovary c. 0.95 mm diam, densely pubescent; styles 0.1 – 0.2 mm long; stigma linear, c. 1.3 mm long, deeply bifid into 2 arms, each arm c. 1 mm long, slightly thickened near base. Fruits c. 1.2 cm diam, brown, sparsely puberulent, persistent sepals not accrescent; wall c. 0.35 mm thick, exocarp partly detaching. Seeds c. 7 mm diam. Distribution — Philippines (endemic). Note — The species is only known from the type. The description is based on Quisumbing (1930). Due to the insufficient specimen seen, especially the lack of staminate flowers, the species is regarded doubtful here. It is probably a synonym of T. filiformis.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
03CA2B5BF76F7372FFDCF9B4FB429908.taxon	distribution	Distribution — Philippines (endemic). Notes — 1. Only known from the type collection. No staminate flowers are available, which makes the generic identification uncertain, but the petals and trifid styles are typical for Trigonostemon, though not exclusively. 2. The development of the stipules seemed to be con- strained, only two very obscure elevations with a few hairs were found instead of normal stipules.	en	Yu, R. - Y., Welzen, P. C. van (2018): A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia. Blumea 62 (3): 179-229, DOI: 10.3767/blumea.2018.62.03.04, URL: https://doi.org/10.3767/blumea.2018.62.03.04
