Phyllagathis ulu C.W. Lin, C.F. Chen & T.Y.A. Yang., 2017

Lin, Che-Wei, Chen, Chien-Fan & Yang, T. Y. Aleck, 2017, Ten new species of Phyllagathis (Trib. Sonerileae, Melastomataceae) from Sarawak, Borneo, Phytotaxa 302 (3), pp. 201-228 : 219

7. Phyllagathis ulu C.W. Lin, C.F. Chen & T.Y.A. Yang. sp. nov. ( Fig. 14 , 15 A–C ).

Type: MALAYSIA. Borneo, Sarawak, Sri Aman Division, Lubok Antu, Batang Ai, ca. 200 m elev. Type specimen pressed from plants cultivated in a nursery in Hong Kong, 9 July 2014, C. W. Lin 575 (holotype TAIF).

Diagnosis: Phyllagathis ulu is very different from other Bornean species in its narrowly obovate leaves with short petioles. The new species superficially resembles P. gigantifolia Nayar (1976: 231) , but differs from it because of the densely puberulous stem (vs. sparsely covered with minute glandular trichomes); smaller leaves, 19.5–32 × 5.7–9 cm (vs. 24–38 × 10–18 cm) and acrodromous suprabasa veins (vs. basal); umbelliform inflorescence (vs. thyrse); and cup-shaped capsules (vs. obconical).

Caulescent herb, erect or ascending, terrestrial. Stems unbranched, green to brown, to 50 cm tall, 0.5–1.2 cm diam., terete, woody at the base, densely brown appressed puberulous and velutinous; internodes 0.8–3(–10) cm long. Leaf blades 4–8, decussate, equal or slightly unequal, oblanceolate to narrowly panduriform-obovate, 19.5–32 × 5.7–9 cm; base cordate or slightly auriculate, margins entire, apex acuminate to short caudate; thick chartaceous to thin coriaceous; venation acrodromous, ca. 7 veined, 1 primary vein and 2 pairs of suprabasal secondary veins, often symmetrical at union with midvein, the first pair produced 1.7–5 cm from the leaf base, a second pair produced 4.3–7 cm from the first pair, positioned 1–2 cm in from margin at widest part of blade; veins slightly depressed on the adaxial surface and prominent on the abaxial surface, secondary and tertiary veins numerous and conspicuous, reticulate or slightly trellis-like; adaxial surface olive green to lime green, glabrous, but appressed puberulous on midrib and main veins, densely towards base; abaxial surface pale green, densely appressed puberulous on all veins. Petioles 5–17 mm long, slightly grooved and flat terete, densely appressed puberulous and velutinous. Bracts green, narrowly ovate, ca. 1 × 2.5 mm at the base of the inflorescence; margins ciliate, adaxially glabrous, abaxially puberulous. Inflorescences in the upper leaf axils, umbelliform, peduncle 5–10 cm, reddish, puberulous; Flowers (not seen) tetramerous, according to the capsules. Sepals 4, persistent, widely triangular, connate into a rim, each lobe with a caudate, angled triangular keel, ca. 1.5 mm long; Capsules on pedicels 8–15 mm long, puberulous. hypanthium cup-shaped, subquadrangular, 8-ribbed, 3–4 × 3–3.5 mm, ovary crown lobes large, with connate lobes, margins entire or slightly repand; placentae disintegrating after seed dehiscence.

Distribution and ecology: Endemic to Batang Ai, Sarawak ( Fig. 3 ), near the border of Indonesia. Frequent in foggy mountain ridges, on semi-shaded slopes in lowland mixed dipterocarp forest, elevation 150 to 400 m.

Etymology: Malay, ulu= upriver; referring to the new species being discovered in upstream Batang Ai.

Figures

FIGURE 3. Distribution maps of Phyllagathis lii, P. millelunata, P. rivularis, P. rubrosetosa, P. ulu, (stars); P. phyllioides, P. violinifolia, P. yodae (solid circles); P. bicolor (solid triangles); P. wallacei (solid squares) in Sarawak, Borneo.

FIGURE 14. Phyllagathis ulu C.W. Lin, C.F. Chen & T.Y.A. Yang. A. Habit; B. Capsule, apical view; C. Old capsule, side view.All from C.W. Lin 575 (TAIF).

FIGURE 15. Phyllagathis ulu C.W. Lin, C.F. Chen & T.Y.A. Yang. A. Habit and habitat; B. Infructescences; C. Capsules, apical view. Phyllagathis violinifolia C.W. Lin, C.F. Chen & T.Y.A. Yang. D. Habit and habitat; E. Leaf, adaxial surface; F. Adaxial leaf surface; G. Abaxial leaf surface, H, I. Capsule, side and apical views;. B–C from C.W. Lin 575; E–I from C.W. Lin 590 (TAIF).