Phyllagathis violinifolia 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 : 219-220

8. Phyllagathis violinifolia C.W. Lin, C.F. Chen & T.Y.A. Yang , sp. nov. ( Fig. 15 D–I , 16 ).

Type: MALAYSIA. Kuching Division, Federal Route No. 1, from Jalan Lundu to Sematan, ca. 100 m elev. Type specimen pressed from plants cultivated in a nursery in Hong Kong, 9 July 2014, C. W. Lin 590 (holotype TAIF)

Diagnosis: This new species can be easily recognized by its smaller panduriform-obovate leaves that are quite different from any other Bornean species. In habit, Phyllagathis violinifolia is similar to P. dispar ( Cogniaux 1891:479) Hansen (1982: 559) but differs from it by the panduriform-obovate leaves (vs. elliptic), the leaves equal or slightly unequal in a pair (vs. unequal), with suprabasal veins (vs. basal); inflorescence peduncle 1–3 cm long (vs. sessile or subsessile); and appressed strigose hypanthium (vs. sparse uniseriate hyaline hairs or glabrous).

Caulescent herb, erect or ascending, terrestrial. Stems unbranched or with few branches, grey green to olive, 10–25(– 45) cm tall, 1.5–5 mm diam., terete, densely and minutely appressed strigose; internodes 0.5–5 cm long. Leaf blades many, decussate, equal or slightly unequal, thin coriaceous, narrowly panduriform-obovate, 3.5–7 × 1.2–2(–2.5) cm; base attenuate to obtuse, margins subentire with rows of appressed pale-brown strigose trichomes up to 1 mm long, apex acuminate to acute; venation acrodromous, ca. 3(–5) veined, 1 primary vein and 1 pair of suprabasal secondary veins, often symmetrical at union with midvein, produced 1–2.5 cm from the leaf base, positioned 1.5–3.5 cm in from margin at widest part of blade; vein 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 grey green to olive green, sparsely minute appressed strigose, abaxial surface pale green, densely minute appressed strigose on all veins. Petioles 3–15 mm long, slightly grooved, densely appressed strigose. Bracts persistent, inconspicuous, succulent, triangular, green, ca. 1 mm long at the base of the inflorescence, appressed strigose. Inflorescences in the upper leaf axils, sparse pleiochasia usually with 1–4 flowers, peduncle 1–3 cm, reddish, densely appressed strigose. Flowers (not seen) tetramerous, according to capsules. Sepals 4, persistent, widely triangular, connate into a rim, each lobe with an caudate, angled, triangular keel, up to 2 mm long; Capsules on pedicels 7–12 mm long, appressed strigose. hypanthium cup-shaped, non-ribbed, 3–4 × 3–3.5 mm, placentae disintegrating after seed dehiscence.

Distribution and ecology: Riparian on semi-shaded riverbanks, along blackwater streams in lowland mixed dipterocarp forest of western Kuching Division, Sarawak ( Fig. 3 ). It grows on humid, steep slopes along stream, under semi-shaded places in lowland forest at 100 m elevation.

Etymology: The epithet refers to the panduriform-obovate leaves.

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 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).

FIGURE 16. Phyllagathis violinifolia C.W. Lin, C.F. Chen & T.Y.A. Yang. A. Habit; B. Leaf, adaxial view; C. Adaxial leaf surface; C’. Abaxial leaf surface; D. Capsule, side view.All from C.W. Lin 590 (TAIF).