Microcos globulifera (Mast.) 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 : 281-284

4. Microcos globulifera (Mast.) Burret — Fig. 6 ; Map 4

Microcos globulifera (Mast.) Burret (1926) 779; I.M.Turner (1997) 487; I.M.Turner et al. (1997) 3. — Grewia globulifera Mast. (1874) 391; King (1891) 112;Ridl.(1922) 302; Kochummen (1973) 397.— Lectotype (designated here): Maingay 1576 (holo K; iso K), Peninsular Malaysia, Malacca.

Microcos blattaefolia (Corner) R.S.Rao (1949) 299, p.p. (quoad specim. Maingay 245 et Maingay 1576A).

Medium-sized tree to 18(– 21) m tall, dbh to 25(– 40) cm; buttresses absent, with slightly fluted bole at the base. Outer bark smooth and sparsely lenticellate, brownish grey to reddish brown; inner bark light brown to brown, outer part granular, inner part fibrous; sapwood pale yellow to white; heartwood pale brown. Twigs smooth, greyish brown to dark brown, densely covered with tufted hairs when young, glabrescent or glabrous when older. Stipules early caducous. Leaves yellowish green to olive-green on both sides, subcoriaceous, minutely scabrous or sparsely covered with simple and tufted hairs on midrib and secondary veins above, sparsely covered with simple and tufted hairs beneath; petioles (10 –)11–18(–23) mm long, (1.5–)2 –2.5(– 3) mm thick, yellowish brown to brown, apically not swollen, densely covered with tufted hairs; blade elliptic to broadly elliptic or sometimes slightly obovate, inequilateral, (10–)12– 23(–25) by (7–)8 –12(–14) cm, base rounded or sometimes obtuse, margin entire, not ciliate, apex acute or sometimes shortly and abruptly acuminate, acumen 0.5–1(–1.5) cm long with a blunt 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 more than 45° with the midrib; domatia absent; tertiary veins scalariform, obscure above, rather thin but conspicuous beneath. Inflorescences Type B panicles, 4 –8(–12) cm long, terminal and axillary, densely covered with tufted hairs; bracts early caducous; involucral bracts of outer whorl unlobed, elliptic, 6–7 by 4– 4.5 mm long, apex broadly acute, or sometimes 2-lobed, lobes ovate, 1–2 mm long, apex acute, rugose outside, densely covered with tufted hairs on both sides, that of inner whorl lanceolate or narrowly elliptic, 4.5 –5.5 by 1.5 – 2.5 mm, apex acute, densely covered with tufted hairs on both sides. Flower buds oblong, 3 – 4 by 2 – 3 mm, densely covered with tufted hairs; pedicels 0.4– 0.5 mm long, c. 0.5 mm thick, densely covered with tufted hairs; sepals oblong, 5.5– 8 by 1.2 –2.2 mm, densely covered with tufted hairs on both sides; petals 5, linear or lanceolate, 3– 3.5 by 0.5 –1.5 mm, apex shortly acuminate or acute, outside sparsely covered with tufted hairs at base and glabrous towards the apex, inside sparsely covered with tufted hairs around the glands to c. 0.5 of its length and glabrescent towards the apex; glands globose or sometimes absent; androgynophore shallowly cup-shaped in outline, 0.7–1 mm long, c. 0.8 mm diam, smooth, glabrous, apical part slightly expanded outwards, with undulate, pubescent rim; stamens with filaments 2–5.5 mm long, glabrous, anthers c. 0.5 mm diam; ovary 3-locular, ovoid, 1.2 –1.5 mm diam, transversely elliptic in cross section, densely covered with tufted hairs; style 3– 3.5 mm long, glabrous. Infructescences densely covered with tufted hairs. Fruits ripening orange, obovoid, smooth, 2.5 –3 by 1.5– 2.5 cm, drying yellowish brown to brown, densely covered with tufted hairs; apex rounded, without pseudostalk; exocarp membranous; mesocarp 5– 8 mm thick; endocarp thin-coriaceous. Fertile pyrene 1, 1-seeded, 6 – 8 mm long; sterile pyrene inconspicuous.

Distribution — Peninsular Malaysia and Singapore.

Habitat & Ecology — In mixed dipterocarp forest on sandy soil; on hillsides or ridge tops, near streams, to 300 m altitude. Flowering: February– June,August; fruiting: March–April, June, August– September.

Vernacularnames — Chenderairimba,damak-damak,damak-damak bulu, damak-damak merah, dedamak, menamak, salut sabul (Malay).

Uses — Ripe fruits edible (Wray 3779).

Notes — Microcos globulifera is sometimes confused with the very variable M. latifolia because of its leaf shape. The present species differs from M. latifolia (especially the Peninsular Malaysian specimens) by its minutely scabrous leaves above (vs glabrous), midrib flattened above (vs impressed), involucral bracts of outer whorl rugose outside (vs smooth), oblong flower buds (vs broadly obovoid), shallowly cup-shaped in outline and smooth androgynophore (vs concave in outline and shallowly longitudinally grooved), 5 – 8 mm thick mesocarp (vs 1.5– 3 mm thick), coriaceous endocarp (vs woody), one pyrene (vs three), and inconspicuous sterile pyrene (vs conspicuous).

Morphologically, M. globulifera is also similar to M. fibrocarpa , but can be distinguished by its subcoriaceous leaves which are sparsely covered with simple and tufted hairs beneath (vs chartaceous, densely covered with soft simple and tufted hairs), entire non-ciliate margin (vs distantly and obscurely serrulate, ciliate margin), blunt acumen tip (vs pointed), and flattened midrib and secondary veins above (vs impressed), as well as by its floral characters.

Figures

Map 4 Distribution of Microcos globulifera (Mast.) Burret ($) and M. latistipulata (Ridl.) Burret var.latistipulata (:) in Peninsular Malaysia and Singapore.

Fig. 6 Microcos globulifera (Mast.) 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. abaxial surface of petal; g. adaxial surface of petal with gland at base; h. stigma; i. fruiting leafy twig; j. longitudinal section of fruit (a, b: Razali R 203; c, d: Ogata KEP 105036; e–h: Maingay 1576; i: Ng FRI 1405; j: Cockburn FRI 7054). — Drawn by R. Wise, FHO.