Phyllagathis phyllioides 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 : 211

4. Phyllagathis phyllioides C.W. Lin, C.F. Chen & T.Y.A. Yang , sp. nov. ( Fig. 8 , 9 ).

Type:— MALAYSIA. Borneo, Sarawak, 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 Taiwan, 25 August 2013, C. W. Lin 556 (holotype TAIF).

Diagnosis:The new species can be easily distinguished from other single stemmed Bornean herbs with tetramerous flowers and panduriform leaves. Phyllagathis phyllioides is somewhat similar to P. elliptica but differs from the latter in the densely appressed puberulous stem (vs. erect velutinous); widely panduriform-obovate leaves (vs. elliptic or obovate), up to 18 cm long (vs. up to 11.5 cm long); inflorescence peduncle 4.2–6 cm long (vs. almost sessile or peduncle up to 1 cm long), inflorescence a congested pleiochasium (vs. umbelliform); anthers purplish (vs. yellow), and ovary crown lobes absent (vs. present).

Caulescent herb, erect or ascending, terrestrial. Stems unbranched, 16–30 cm tall, 0.3–0.5 cm diam., terete, minute densely appressed strigose, glabrescent later; internodes 1.5–3.2 cm. Leaf blades 4–6, decussate, equal or slightly unequal, thick chartaceous to thin coriaceous, widely panduriform-obovate, 9.5–18 × 5–10 cm wide; base cordate, slightly auriculate, margins entire with rows of minute appressed puberulous, ca. 1.2 mm long, apex acuminate; venation acrodromous, ca. 5 (–7) veined, 1 primary vein and 1 pair of suprabasal secondary veins, often slightly asymmetrical at union with midvein, produced 7–15 mm from the leaf base, positioned 0.7–2 cm in from margin at widest part of blade; vein 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 lime green, with sparse minute strigose, densely on veins; abaxial surface pale green, densely appressed strigose and puberulous on all veins. Petioles 7–18 mm long, slightly grooved and flat terete, densely strigose. Bracts caducous, inconspicuous. Inflorescences in the upper leaf axils, congested pleiochasium, peduncle 4.2–6 cm, pale green, densely appressed strigose and with sparse glands. Flower tetramerous, pedicels 3.5–5 mm long, with pale-brown appressed strigose. Hypanthium campanulate, ca. 2.5 mm long and wide, appressed strigose and with sparse minute glands. Sepals 4, persistent, widely triangular, connate into a rim, each lobe with an large caudate, angled, triangular keel, 1.2–1.5 mm long. Petals 4, oblique, widely ovate, 4–4.8 × 1.8–2.3 mm, white, glabrous, apex cuspidate to acuminate. Stamens 8, isomorphic, subequal, filaments slightly flat, 2.5–3.5 mm long, white, anthers narrowly lanceolate, apex attenuate, ventrally curved, slightly undulate, 2–3.1 mm long, pale magenta to bluish, pore 1, connective distinct, ventrally with one pair of tuberculate appendages on base of anther sacs, dorsally with a minute dorsal appendage at the base, appendage tuberculate, apex retuse. Style filiform, ca. 7 mm long, glabrous, stigma capitate. Ovary 3/4 as long as the hypanthium, crown lobes absent, anther pockets shallow, placentae stalked. Capsules on pedicels to 1 cm long, hypanthium cup-shaped, non-ribbed, 3.5–4 × 3.5 mm, placentae disintegrating after seed dehiscence.

Distribution and ecology: Endemic to western Kuching Division, Sarawak ( Fig. 3 ). It grows in riparian forest and humid steep slopes along a stream in semi-shaded lowland forest, at ca. 100 m elevation.

Etymology: The specific epithet refers to the resemblance of this new species panduriform leaves to the leaf insect genus “ Phyllium ”.

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 8. Phyllagathis phyllioides C.W. Lin, C.F. Chen & T.Y.A. Yang. A. Habit; B. Abaxial leaf surface; B’. Adaxial leaf surface; C. Bracts, adaxial view; D, D’. flower, face and side views; E, E’. Petal, both surfaces views; F, F’, F’’, G, G’. Stamens, ventral, dorsal and side view; H. Style; I. Vertical section of the ovary; J. Capsule, side view.All from C.W. Lin 556 (TAIF).

FIGURE 9. Phyllagathis phyllioidesC.W.Lin,C.F.Chen &T.Y.A.Yang.A,B.Habit and habitat;C.Leaf, abaxial surface;D.Inflorescence; E, F. Flower, face and side views; G, H. Stamens, outer and inner whorl; I. Vertical section of the ovary; J, K. Capsule, apical and side views. B–K from C.W. Lin 556 (TAIF).