Dimorphocalyx muricatus (Hook.f.) Airy Shaw

6. Dimorphocalyx muricatus (Hook.f.) Airy Shaw View in CoL — Fig. 1g View Fig , Map 3

Dimorphocalyx muricatus (Hook.f.) Airy Shaw (1967) View in CoL 412; (1972a) 252; Whitmore (1973) 87; Airy Shaw (1975) 97;(1981) 286; Phattar. & Chayam. (2005) 231, f. 51, pl. XIII: 1. — Ostodes muricata Hook.f. (1887) View in CoL 401; Pax & K.Hoffm. (1911) 21; Ridl. (1924) 269. — Ostodes muricata Hook.f. var. genuina Pax (1911) 21, nom. inval. — Type: King’s collector 3162 (holo K), [ Malaysia,] Perak, Larut.

Trigonostemon asahanensis Croizat (1942) View in CoL 54. — Type: Rahmat si Boeea 9872 (holo A; iso L), Sumatra, Asahan, vicinity of Tomoean Dolok .

Dimorphocalyx View in CoL [!] sp.?, Merr. (1929) 163. — pro Elmer 21287 ( L), British North Borneo [= Sabah], Elphinstone Prov., Tawao .

Ostodes muricatus Hook. f.var .? minor Hook.f.(1887) 401. — Dimorphocalyx muricatus (Hook.f.) Airy Shaw var. minor (Hook.f.) Airy Shaw (1967) View in CoL 412; Whitmore (1973) 87. — Lectotype (designated here): Lobb 304 (holo BM; iso E, GH, 2 sheets, K, L), Singapore.

Small shrubs to trees, to 10(–25) m high, dbh to 18 cm, evergreen but seemingly deciduous in S Thailand, young leaves when flowering; flowering branches 2–5.5 mm thick, ± angular, light grey (to brown) when dry, striate when dry, smooth to lenticellate, mainly glabrous. Indumentum variably present. Outer bark grey to brown, smooth (to scaly and hooped), soft, papery, c. 0.2 mm thick; inner bark yellow to orange-red to red, soft, (laminated, fibrous), c. 2 mm thick; exudate watery, red; sapwood creamy white to pale yellow. Stipules triangular, 5–8 by 3–4 mm, glabrous to hairy outside, early caducous. Leaves: petiole (1.1–) 3–14 cm long, (0.8–) 1–4 mm diam, deeply furrowed above, glabrous to hairy, basally and apically slightly pulvinate; blade (ovate to) elliptic to oblong (to obovate), widest in ± middle, 6.8–42 by 2.6–13.2 cm, 1.9–3.7 times as long as wide, papyraceous to pergamentaceous (to coriaceous), base round to obtuse to cuneate, margin serrate (to serrulate), flat to revolute, with glands abaxially in the teeth, apex acuminate to usually cuspidate, upper surface dark green, at most hairy on midrib, lower surface pale green to blue-green, sometimes a bit hairy on venation, latter flat to slightly raised above, raised below, secondary veins 12–15 pairs, intercalary nerves often present, tertiary nerves scalariform, higher orders reticulate. Inflorescences axillary thyrses, to c. 19 cm long, but usually less than 5 cm long, staminate ones more or less paniculate with a few side-branches, pistillate ones often almost umbellate or dichasial, glabrous to usually shortly sericeous; staminate flowers several per node, pistillate ones single; bracts ovate (to elliptic), 1.5–4 by 1.2–2 mm, usually hairy outside, glabrous inside. Flowers: calyx lobes mostly hairy outside except for lobe margins, glabrous inside, usually with a large, round gland outside, often indistinct. Staminate flowers 14–15 mm diam, white, scented; pedicel 15–17 mm long above abscission zone, roundish to flattened, usually hairy; calyx 5–5.5 mm high, lobes ovate to elliptic, 3–3.5 by 2–4 mm, apex round; petals oblong to obovate, 8–12 by 2.8–4.5 mm, reflexed, glabrous, apex round; disc glands often indistinct, winding around stamens, glabrous; stamens 10–16, not in distinct whorls, only inner c. 3 with connate filaments, latter 3.5–4 mm long, anthers dorsifixed, 1.2–1.4 by 1–1.3 mm, inner ones largest. Pistillate flowers c. 8 mm diam, not strongly scented; pedicel 6–13 mm long above abscission zone, round, hairy; sepals shortly connate, basally white, rest light green, lobes ovate to elliptic 3–6 by 3–4.5 mm, apex rounded; petals oblong to obovate, c. 8 by 6.2–7 mm, white, apex round; disc a thin ring, glabrous; ovary ovoid, 3.5–4.5 by 2–3 mm, densely beset with blunt spines, glabrous, style absent, stigmas 2–3.7 mm long, white to light green, completely split except for lower 0.5–1 mm, upper surface stigmatic. Fruits 1.8–3.5 by 1.5–2.7 cm, muricate with spines often united into short ledges, dark green to pink-yellow to brown, wall woody, c. 2 mm thick, exocarp and endocarp usually completely separating; pedicel elongated up to 24 mm; sepals slightly enlarged to 8 by 5 mm; columella 10.5–13 mm long. Seeds sub-ellipsoid with usually abaxially a lengthwise ridge, 8–14 by 6–11 by 7–10.5 mm.

Distribution — Thailand (Peninsular: Narathiwat Prov.), Malay Peninsula, Sumatra, Borneo.

Habitat & Ecology — Evergreen forest, primary and (logged) secondary (Dipterocarp) forest, often on ridges and along rivers and swamps; soil varying from yellow clay to sandy clay to sandstone with clay to loam.Altitude: sea level up to 1000 m. Flowering: March to October; fruiting: whole year through.

Vernacular names — Sumatra: Batin batin delok alafai, Batin batin silafai; Kajoe si saram. Borneo: Brunei:Asah anak unyong; Kalimantan: Kupang parawa (Dayak); Sarawak: Bantas (Iban); Marok (Kayan)).