Actephila ovalis (Ridl.) Gage

8. Actephila ovalis (Ridl.) Gage View in CoL — Fig. 6; Map 5 View Map 5

Actephila ovalis (Ridl.) Gage (1922) View in CoL 219; Ridl. (1924) 196; Gage (1936) 519; M.R.Hend. (1939) 68; Smitinand (1962) 139; Airy Shaw (1972) 210; Whitmore (1973) 51; Chayam. (2005) 38, f. 7, pl. II: 1. — Dimorphocalyx ovalis Ridl. (1911) 178; Smitinand (1961) 52, photo. — Syntypes: Curtis s.n. (SING), Malaysia, Lankawi, Kwah; Ridley 14890 (K 2 sheets, SING), Malaysia, Perlis woods at Bukit Telor Jambu, Kanga.

(Sub)shrubs to small trees, up to 5 m high, stem brown; flow- ering branches 1–4 mm diam, with brown to whitish lenticels, puberulous. Indumentum of simple hairs, most parts subglabrous. Stipules narrowly ovate to narrowly triangular, 1.5–4 by 0.8–1.5 mm, outside strongly sericeous when young, often glabrous. Leaves alternate to subopposite; petioles 2–6(–13) mm long, completely pulvinate, strongly puberulous; blade elliptic, 6.4–15.4 by 2.1–4.9 cm, 2.7–3.8(–4.4) times as long as wide, papyraceous, base attenuate to acute, margin wavy, apex narrowly to widely cuspidate, sometimes more acuminate, adaxially mid to dark green, abaxially slightly lighter green, sometimes somewhat puberulous basally on midrib; nerves 10–17 per side. Flowers solitary, on older branches on small brachyblasts; petals: apex truncate to rounded, erose; disc a thick fleshy ring. Staminate flowers c. 5 mm diam; pedicel 2–4 mm long, widening towards apex, glabrous to sericeous, cream-coloured; sepals ovate, widest just below the middle, c. 2 by 1.2–1.5(–2) mm, light greenish to cream, margin slightly membranous, apex rounded or somewhat obtuse, outside hairy; petals c. 2 by 0.9 mm, white; disc covering base of sepals, whitish; anthers yellow to orangish; pistillode small. Pistillate flowers green; sepals: lobes obovate, 2 smaller, c. 3.5 by 3 mm, 3 larger obovate, c. 5 by 4.5 mm, enlarging in fruit, green; petals 1.4–1.5 by 0.5–0.7 mm; disc substantially covering sepal base

Fig. 6 Actephila ovalis (Ridl.) Gage ( Phyllanthaceae ceae). Habit with dehisced fruit and enlarged sepals ― Drawing by Esmée Winkel, 2016.

in fruit; ovary ovoid, slightly 3-lobed, c. 1.2 by 1.6 mm, greenish; style c. 0.5 mm long; stigmas c. 1.5 mm long, cream to purple, apically slightly split. Fruits 1.6–1.8 cm diam, (green to) pale green to yellowish green; pedicels (25–)30–70 by 0.4–0.9 mm, straight, not widening towards apex, often somewhat striate when dry, apically remaining somewhat puberulous; sepals enlarged, elliptic, widest in the middle, (10–)13–22 by 9–15 mm, margin entire, apex rounded, venation parallel, 4–8 main veins, basally slightly hairy outside, otherwise glabrous; wall with knobbly surface, sericeous, especially when developing fur-like, thin; columella 5.5–7 mm long, fibrous after dehiscence. Seeds (6–)8.5–9(–12) mm long, (4–)7–8(–9.5) mm wide, (4–)5–7(–8) mm high, widened seeds 8–9 mm long, 8–9 mm wide, 6.5–7 mm high.

Distribution — S South-western and Peninsular Thailand, N Malay Peninsula.

Habitat & Ecology — Evergreen forest; soil: limestone or rarely granite.Altitude: sea-level up to 200(–457) m. Flowering and fruiting: more or less throughout the year.

Notes — 1. Typical for the species are the enlarged sepals of the calyx when fruiting, the sericeous fruit wall and the long straight fruiting pedicels. When not fruiting this species is easily confused with A. subsessilis (see note under latter for differ- ences).

2. Actephila collinsae , also a species with enlarged sepals in fruit, is endemic in SW Thailand and partly overlaps in distribution with A. ovalis in the province Prachuap Khiri Khan (SW Thailand). Actephila ovalis differs from A. collinsae in the leaf apex (obtuse to bluntly acute in A. collinsae vs acuminate to cuspidate in A. ovalis ), leaf margin (flat in A. collinsae , wavy in A. ovalis ) and fruiting pedicel and sepals (glabrous in A. collinsae vs slightly hairy on the apical pedicel part and basal sepal part outside in A. ovalis ).

3. Gagnepain described several Indochinese species (1925: A. macrantha ; 1924: A. nitidula , A. pierrei and A. platysepala ) with enlarged sepals in fruit. These have not been assessed, but as they were published later than the epithets collinsae and ovalis , a possible synonymization will not invoke a name change.