Syzygium galanthum Brambach, Byng & Culmsee, 2017

Brambach, Fabian, Byng, James W. & Culmsee, Heike, 2017, Five new species of Syzygium (Myrtaceae) from Sulawesi, Indonesia, PhytoKeys 81, pp. 47-78 : 67-71

5. Syzygium galanthum Brambach, Byng & Culmsee sp. nov. Figures 4 , 7 , 8

Myrtaceae " sp. 7" ( Culmsee and Pitopang 2009)

Diagnosis.

Syzygium galanthum is similar to Syzygium hylochare (Diels) Merrill and Perry (1942, 249) from New Guinea but differs from that species in larger leaves (usually 15-22 vs 8-14 cm long), more slender flowers with longer anthopodia (5-10 vs 3-5 mm) and milky white petals (vs pink or red). It is also similar to the widely cultivated Syzygium malaccense (L.) Merrill & Perry (1938b, 215) but has subangular (vs clearly angular) and more slender branchlets (2-3 vs 6-8 mm in diameter), smaller, chartaceous leaves (vs coriaceous), more slender inflorescences, more slender flowers with longer anthopodia (5-10 mm vs 0-5 mm), hypanthia which dry reddish brown with many black glands (vs drying dark brown without conspicuous glands), and creamy-white petals (vs pink or red). Floral formula B1 Bt2 K2:2┼ C4* A∞* Ĝ (2)┼ Vx∞.

Type.

INDONESIA. Central Sulawesi (Sulawesi Tengah): LLNP, Kab. Poso , Kec. Lore Tengah, 3.5 km NE of Rompo, following road to Katu for 3 km, then following footpath N for 2 km, tree-inventory plot Tarara , 1°35.3'S 120°17.0'E, 1200 m, 29 Nov 2011: Brambach F, Mangopo H, Firdaus, Faber M, Tiranda R 1316 (flowers; holotype L[L.3962132]!; isotypes BO [BO-1938381]!, CEB, GOET [GOET020017]!, K [K000993484]!) .

Description.

Trees, up to 25 m tall, diameter at breast height ≤ 30 cm, trunk straight, ≤ 15 m tall, with buttresses 0.4 m tall, sometimes with stilt roots. Outer bark bright- or rusty red, peeling off in thin sheets, inner bark pale or dark red, wood straw or cream-coloured. Young branchlets 1-2 × 2-3 mm, subangular, flattened, epidermis olive, drying reddish brown, striate; becoming ± terete, bark (reddish) brown, striate or fissured, later peeling off in small thin sheets.

Leaves (sub-)opposite. Petioles 6-18 × 1-3 mm, channelled above, rounded beneath, turning corky, pale brown, drying (reddish) brown. Blades (10-) 12-23 (-26) × (4-) 5.5-7.5 (-9) cm, ratio (1.7-) 2.5-3.2 (-3.5), (narrowly) elliptic or rarely oblanceolate, base acute, obtuse, or rounded, apex acuminate, acumen often recurved, margin flat or revolute; chartaceous, glossy green and often ± bullate above, paler green beneath, drying dull and (greyish or olive) brown above, dull and (yellowish or greyish) brown beneath; pellucid dots scattered or numerous, usually visible on lower surface and sometimes also on upper surface. Midrib channelled above, prominent, rounded, drying pale or reddish brown, striate and with dark gland dots beneath. Secondary vein pairs (6-) 8-10 (-12), 7-25 mm apart, prominulous or not, concolorous with the lamina and usually inconspicuous above, prominent and concolorous with or more reddish than the lamina beneath; intersecondary veins present. Tertiary veins reticulate, lax, prominulous or not, concolorous with the lamina and usually inconspicuous above, prominent and concolorous with or more reddish than the lamina beneath. Inner intramarginal vein 3-8 mm from leaf margin, (strongly) looping; outer intramarginal vein 1-3 mm from leaf margin.

Inflorescences axillary on leafless portion of the twigs, often fascicled, lax, (sub-)sessile botryoids or monads, 3-5 cm long, peduncles absent or ≤ 1 cm long, axes angular, drying (reddish) brown with many black gland dots, turning corky at the base, often with conspicuous whitish blisters. Bracts c. 0.5 mm long, early caducous; bracteoles 2 per flower, similar to bracts.

Flowers 1-8 per inflorescence, within the inflorescence in monads, 4-merous, only known before anthesis, mature buds 15-25 × 5-7 mm, anthopodium 5-10 (-14) mm long, slender. Hypanthium 7-11 × 5-7 mm, infundibuliform, pale green, drying dark reddish brown, wrinkled, densely black gland-dotted and with conspicuous whitish blisters, hypanthium rim 3 mm long. Calyx lobes 2 × 3-5 (outer) and 3-4 × 5-7 (inner) mm, broadly rounded with thin hyaline margins, greenish white, drying red, sparsely gland-dotted. Petals c. 8 × 6 mm, hood shaped before anthesis, milky white, drying yellowish red, faintly veined and densely pellucid-dotted. Stamens c. 100, filaments 4 -10 mm long before anthesis, yellowish green, anthers c. 1 mm long, ovoid or ellipsoid, yellow. Ovary bilocular, locules surrounded by spongy tissue, ovules many per locule, ascending. Style 10 mm long before anthesis, pointed, green.

Fruits and seeds unknown.

Etymology.

The species name derives from the Greek γάλα (milk) and άνθος (flower) and refers to the petals’ milky white colour (Figure 7g, j ). The colour pattern of the flowers is furthermore similar to the one found in the amaryllidaceous genus Galanthus Linnaeus (1753, 288).

Phenology.

The type specimen was collected with mature flower buds in late November, suggesting flowering in December.

Distribution and habitat.

Syzygium galanthum is currently only recorded from LLNP in the province of Central Sulawesi (Figure 4 ). There it occurs scattered in undisturbed submontane forest at three localities from 700-1200 m over Sideralic Cambisols and mollic Umbrisols derived from varied parent material. The forests at these localities were dominated by species of Fagaceae , Lauraceae , Moraceae , and Sapotaceae , among others.

Conservation status.

Syzygium galanthum has a limited geographical distribution (estimated EOO 140 km²) and seems to be restricted to submontane forest between 700 and 1200 m. We assume that the estimated AOO of 12 km² is unrealistically low, due to limited collection activities in Central Sulawesi. However, despite being inside the protected LLNP, recent deforestation activities have been detected near one of the collection sites (Pono inventory plot, detected using the Global Forest Change website, Hansen et al. 2013), possibly related to the establishment of cocoa plantations (Aiyen Tjoa, Tadulako University, personal communication June 2015). Given the ongoing deforestation activities in the species’ narrow geographical range and the recommendation to use a precautionary attitude in conservation assessments ( IUCN Standards and Petitions Subcommittee 2014) we propose a preliminary extinction risk assessment of “Endangered” (EN B1ab(i,ii,iii)).

Vernacular name.

Tambeanitu (Bahasa Behoa, Brambach et al. 1316).

Notes.

In the field, S. galanthum can be recognised by the leaves with corky petioles and rather few, ± arching secondary veins. Similar corky petioles occur in S. peregrinum (Blume) Merrill & Perry (1939, 154) from Borneo and the Southern Philippines. A peculiarity is the presence of white blisters on the inflorescence axes and flowers of dried material (Figure 7h, k ). These blisters were not observed in fresh state and must have appeared during the drying process.

It appears that there is a group of morphologically similar species in Malesia, all characterised by pale-drying leaves with rather few secondary veins, inflorescences below the leaves, and medium-sized to large, showy, infundibuliform flowers with short or long anthopodia and either white or red/pink petals and stamens: e.g. S. iliasii Ashton (2011, 222) from Borneo, S. galanthum and several unnamed collections from Sulawesi, S. hylochare , S. laqueatum Merrill & Perry (1942, 257), and S. phaeostictum from New Guinea and possibly the Maluku Islands, and the widely cultivated S. malaccense with unknown geographical origin. As can be seen from material in L, the assignation of specimens to these species has not been consistent in the past and specific limits in the group need to be critically revised.

Additional specimens examined

(Paratypes). INDONESIA. Central Sulawesi (Sulawesi Tengah) , LLNP: Kab. Poso, Kec. Lore Tengah, 3.5 km NE of Rompo, following road to Katu for 3 km, then following footpath N for 2 km, tree-inventory plot Tarara , 1°35.3'S 120°17.0'E, 1200 m, 22 Nov 2011: Brambach F, Mangopo H, Firdaus, Faber M, Tiranda R 1047 (sterile; BO [BO-1938446]!, CEB, GOET [GOET020018]!) & 1083 (sterile; BO [BO-1938445]!,CEB, L!) & 1290 (sterile; BO [BO-1938444]!, CEB, K [K000993485]!) .

Kab. Sigi, Kec. Kulawi, 2.4 km ENE of Toro, NE edge of Pono Valley , tree-inventory plot Pono, 1°29.7'S, 120°03.4'E, 1050 m, 16 Aug 2006: Culmsee 537 (sterile; CEB, K [K000993492]!) & 890 (sterile; BO [BO-1938448]!, CEB); ibid. loco, Jul 2007: Culmsee r497 (sterile; BO [BO-1938449]!, CEB, GOET [GOET020019]!, L!) .

Kab. Sigi, Kec. Kulawi Selatan, 4 km ENE of Watukilo, 400 m N of Mboe River , tree-inventory plot Rantena, 1°36.2'S, 120°04.5'E, 700 m, 17-26 Jun 2011: Brambach F, Mangopo H, Firdaus, Faber M, Tiranda R 0533 (sterile; BO [BO-1938447]!, CEB, L!) .

Figures

Figure 4. Distribution map of four species of Syzygium in Central Sulawesi: Syzygium contiguum (orange diamonds), S. devogelii (yellow dots), S. eymae (light blue square), and S. galanthum (green triangles). Lore Lindu National Park is indicated by a black line. Map created with QGIS (QGIS Development Team 2016) using the digital elevation model of Jarvis et al. (2008).

Figure 7. Morphological characters of Syzygium galanthum. a trunk, c. 15 m tall b upper side of leaves c branchlet tip with smooth younger petioles d older corky petioles e underside of leaf f bark slash g mature flower buds in fresh state h dried mature flower bud with apical part of inflorescence axis and white blister on the anthopodium i longitudinal section of mature flower bud in dried state j branch with mature flower buds below the leaves k detail of dried, fascicled inflorescences. a-b and f-k type collection Brambach et al. 1316 c and e Brambach et al. 1083 d Brambach et al. 1047. All scale bars: 1 cm.

Figure 8. Leaves of all new species described. Variation of Syzygium balgooyi (a-e), S. contiguum (f), S. devogelii (g), S. eymae (h), and S. galanthum (i). a Brambach et al. 0283 b Brambach et al. 0681 c Brambach et al. 1333 d de Vogel 5413 [L. 2517563] e Culmsee r 2162 f Culmsee r 463 g Brambach et al. 0818 h Eyma 3624 [L. 2535689] i Brambach et al. 0533. Scale bar: 10 cm, valid for all leaves.