Microcos hirsuta (Korth.) Burret

Chung, R. C. K. & Soepadmo, E., 2011, Taxonomic revision of the genus Microcos (Malvaceae-Grewioideae) in Peninsular Malaysia and Singapore, Blumea 56 (3), pp. 273-299 : 284-286

5. Microcos hirsuta (Korth.) Burret — Fig. 7 ; Map 5

Microcos hirsuta (Korth.) Burret (1926) 782; Whitmore & Tantra (1986) 241; I.M.Turner (1993) 221; (1997) 487; Cheek & I.M.Turner (1995) 129; R.C.K. Chung et al. (2005b) 110. — Omphacarpus hirsutus Korth. (1842a) t. 42; (1842b) 193. — Grewia omphacarpa Miq. (1859) 204; Ridl. (1922) 301. — Grewia hirsuta (Korth.) Kochummen (1973) 39, nom. illegit.& nom. superfl., non G. hirsuta Vahl (1790) 34; Whitmore & Tantra (1986) 240; Keng (1990) 88. — Lectotype ( Chung et al. 2005b): Korthals s.n. (holo L, acc. no. 908.253-200; iso L, acc. nos. 944.56-122–124, 908.253-353, 908.253-341–342), Borneo, Kalimantan, Doesoen River.

Grewia palembanica Miq. (1861) 405. — Type: Teijsmann HB 3658 (BO, L, acc. no. 908.253-799, U n.v.), Sumatra, Palembang, Muara Enim .

Small tree to 15 m tall, dbh to 20 cm; buttresses absent. Outer bark smooth, greyish brown; inner bark pale orange to pinkish brown, fibrous; sapwood pink to white. Twigs smooth, dark brown to black, densely covered with stellate hairs when young, glabrescent when older. Stipules 4 – 6 mm long, 3– 4-lobed or 3 – 4-cleft, lobes oblong or lanceolate, 2– 4 mm long, glabrescent on both sides, caducous. Leaves olive-green on both sides, subcoriaceous, glabrous or sparsely covered with simple and stellate hairs on midrib and secondary veins above, densely covered with simple and stellate hairs beneath; petioles (5–)6 –16(– 20) mm long, 1–2 mm thick, yellowish brown, apically swollen for 4 –10 mm long, densely covered with stellate hairs; blade narrowly elliptic or narrowly oblong, rarely elliptic or oblong, equilateral or sometimes inequilateral, (9–)10 –25(– 32) by (3–)4–10(–13) cm, base obtuse to rounded, margin entire, sometimes ciliate, apex acuminate or acute, acumen 1–2.5(– 3) cm long with a pointed tip; midrib and secondary veins flattened above, raised beneath; secondary veins 7–9 pairs, basal pair reaching between 0.25 and 0.5 of blade length, forming an angle of less than 45° with the midrib; domatia absent; tertiary veins reticulate, inconspicuous above, thin and prominent beneath. Inflorescences Type A and Type B panicles, terminal and axillary, (1–)1.5–3(–6) cm long, densely covered with stellate hairs; bracts 2– 3-cleft, lobes lanceolate, 1–2.5 mm long, densely covered with stellate hairs on both sides, persistent or caducous; involucral bracts of outer whorl 6 – 8.5 mm long, 2 – 3-cleft, lobes ovate, 2 – 4 mm long, apex acute, smooth and densely covered with stellate hairs outside, sparsely covered with stellate hairs inside, that of inner whorl oblanceolate, 4 – 5 by 1.5 – 2 mm, apex acute, densely covered with stellate hairs on both sides. Flower buds oblong, 2.5 – 4.5 2 mm 2 mm 2 mm 3 mm by 1.8– 2.5 mm, densely covered with stellate hairs; pedicels 0.5–2 mm long, 0.6–0.9 mm thick, densely covered with stellate hairs; sepals linear or narrowly oblong, 7–10 by 1.2 –1.5 mm, densely covered with stellate hairs outside, sparsely covered with stellate hairs inside; petals 5, lanceolate, 2 –4 by 0.7–1 mm, apex shallowly 2– 3-lobed, outside covered with stellate hairs at base to c. 0.25 of its length and glabrous towards the apex, inside densely covered with stellate hairs around the glands to c. 0.25 of its length and glabrous towards the apex; glands depressed obovoid; androgynophore concave in outline, 0.7–1.2 mm long, c. 0.8 mm diam, smooth, covered with stellate hairs or glabrescent (in buds) then become glabrous (in flowers), apical part expanded into a platform-like structure of c. 0.2 mm wide, with undulate rim covered with stellate hairs; stamens with filaments 3.2–5 mm long, glabrous, anthers c. 0.2 mm diam; ovary 3-locular, ellipsoid, 1.5 –2 mm diam, circular in cross section, densely covered with stellate hairs; style 3 –3.5 mm long, glabrous. Infructescences sparsely covered with stellate hairs. Fruits ripening bright orange, obovoid, smooth, 2– 2.8 by 1–2 cm, drying yellowish brown to brown, densely covered with stellate hairs; apex rounded, without pseudostalk; exocarp membranous; mesocarp 3 –5 mm thick; endocarp thin-coriaceous. Fertile pyrene 1, 1-seeded, 7–10 mm long; sterile pyrene inconspicuous.

Distribution — Sumatra, Peninsular Malaysia, Singapore and Borneo.

Habitat & Ecology — In alluvial freshwater swamp and mixed dipterocarp forests on yellow sandy soil; on gentle to steep slopes, or ridges, at 25– 900 m altitude. Flowering and fruiting all year round.

Uses — Ripe fruits edible ( Mat Asri FRI 38695).

Figures

Map 5 Distribution of Microcos hirsuta (Korth.) Burret ($) and M. malayana R.C.K.Chung (:) in Peninsular Malaysia and Singapore.

Fig. 7 Microcos hirsuta (Korth.) Burret. a. Flowering leafy twig; b. detail of abaxial leaf surface near midrib; c. flower buds surrounded by involucral bracts; d. longitudinal section of flower bud; e. flower with sepals and petals removed; f. adaxial surface of sepal; g. abaxial surface of petal; h. adaxial surface of petal with gland at base; i. fruit; j. longitudinal section of fruit; k. cross section of fruit (a–h: Korthals s.n. = L acc. no. 908.253.200; i –k: Korthals s.n. = L acc. no. 944.56.122). — Drawn by J. Pao, SAR.