Dicoelia Benth.

van Welzen, P. C., 2011, Revision of Dicoelia (Phyllanthaceae; Euphorbiaceae s. l.), Blumea 56 (3), pp. 209-213 : 209-212

Dicoelia Benth.

Dicoelia Benth. (1879) 70, t. 1289; Pax (1890) 27; Merr. (1921) 330; Pax & K.Hoffm.(1922) 15;(1931) 46; Croizat (1942) 38; Whitmore (1973) 86; Airy Shaw (1975) 95;G.L. Webster (1975) 594;(1987) 6; Mennega (1987) 122, t. 2; G.L. Webster (1994) 67; Stuppy (1995) 158, 166; Radcl.-Sm. (2001) 124. — Type species: Dicoelia beccariana Benth.

(Shrubs to) trees, monoecious, terminal branches angular, pilose, early glabrescent soon. Indumentum simple hairs. Stipules linear-triangular, caducous, apex acute, hairy on both sides. Leaves alternate, simple; petiole mainly round, basally slightly pulvinate, apically clearly pulvinate; blade elliptic to obovate, symmetric, margin entire, upper surface usually glabrous except some hairs on the basal part of the midrib, lower surface usually slightly hairy, venation raised beneath, pinnate, nerves looped and closed near the margin, veins scalariform, veinlets

© 2011 Nationaal Herbarium Nederland reticulate. Inflorescences axillary to subterminal racemiform thyrses (to pseudo-paniculate when subterminal), inserted slightly above the leaves, single per axil (to 2 together, second one much shorter), hairy, round to ribbed when dry, sexes variable, either only staminate with groups of flowers per node, pistillate with single flowers per node, or bisexual with groups of staminate and a central pistillate flower; bracts triangular, apex acute, hairy on both sides; bracteoles like bracts, but smaller; staminate flowers with even smaller subtending bracts. Flowers mainly white: pedicel round, hairy, light green; sepals 5, triangular, valvate, apex acute, hairy on both sides, white or greenish; petals 5, obovate, thick, white hairy on both sides, basal part stipe-like, patent when flowering, pinkish to distally red; disc glands indistinct, especially in staminate flowers, episepalous, small, global, hairy. Staminate flowers: petals cucullate, patent after anthesis, apex involute, hooded, grown together with the raised midrib, forming two cavities on both sides of midrib, midrib elongated as extended, free tip pointing horizontally; stamens 5, basally connate in an androphore, latter widening towards the top, hairy, filaments hairy, rose-pink, anthers elliptic, basifixed, opening introrse with lengthwise slits, both thecae separate, each in cavity of adjacent petals when young, yellow; pistillode hairy, with 5 stigmas extending above petals. Pistillate flowers: petals either straight, with an acute apex or cucullate with rounded apex; gynophore subglabrous, ovary 3- (or 4-)locular, tomentose, 2 ovules per locule, style absent or a short conical extension of the ovary, tomentose, stigmas linear, spatially separate from each other, hairy, apex widened, flat, spathulate, not split, differently coloured when dry. Fruits ovoid, not to slightly lobed, basally concave around gynophore, greyish green when young to brown, brown tomentose, dehiscing septifragally and partly loculicially from above; wall woody, thin, c. 0.8 mm thick; sepals and on Sumatra petals persistent, reflexed; columella pyramidal or slightly T-shaped. Seed ovoid, flattened-triangular on inside, smooth, often slightly notched near hilum, arilloid absent.

Distribution — Two species, both endemic in Malesia, one found on Sumatra, the other on Borneo.

Wood — Wood shows resemblance to Cleistanthus , also part of the Phyllanthaceae ( Mennega 1987) . See also Kathriarachchi et al. (2005) for information on pollen and seed anatomy.