Stemonuraceae

Abstract

Evergreen trees or shrubs. Lower branches self-pruning and leaving conspicuous scars in some genera. Buttresses absent (except Cantleya), stilt-roots and pneumatophores sometimes present (Stemonurus). Leaves simple, alternate, sometimes appearing distichous, entire, penninerved (rarely triplinerved), exstipulate. Inflorescences axillary, terminal or leaf-opposed, occasionally ramiflorous, cymose, rarely reduced to 1 or few flowers. Flowers bisexual or functionally unisexual, actinomorphic, usually 5-merous, usually small (3–6 mm), but Whitmorea up to 1.5 cm. Calyx persistent, articulated with the pedicel, small, generally cupular, sepals 4–5, connate, calyx rim entire, apiculate or shortly lobed. Petals 4–5(7), minute to conspicuous, free (coherent), sometimes united in Gomphandra, often inflexed at apex, lobes valvate, midrib usually thickened ventrally. Stamens isomerous, alternipetalous, filaments filiform (rarely) or broad and flattened, glabrous or with papillose to clavate hairs ventrally, dorsally, and/or at apex of connective; anthers bisporangiate, basifixed, introrse or extrorse (Grisollea), longitudinally dehiscent. Staminodes in pistillate flowers present or absent (Grisollea), resembling stamens or much smaller (Codiocarpus) but pollen sacs sterile. Disk absent or present, cupular, hippocrepiform, or squamiform and unilateral, lobed or entire, persistent in fruit. Ovary superior, carpel apparently 1 but likely pseudomonomerous, unilocular, often with exterior lateral appendage above the disk, ovules 2, apical, pendulous, anatropous, unitegmic. Stigma on short style or more often sessile, peltate, subcapitate, or punctiform (only in bisexual flowers), entire to lobed, crenate, or ridged, often eccentric, persistent in fruit. Ovary rudiment in staminate flowers usually smaller than ovary and occasionally with 2 ovules which do not develop, disk sometimes present, stigma absent or much reduced. Fruit a drupe of various shape, in most genera laterally compressed, when compressed with conspicuous lateral appendage which develops from the ovary wall (except Grisollea). Mesocarp divided into two parts, outer mesocarp usually fleshy, thin, variously coloured, inner mesocarp of sclerified bundles forming prominent longitudinal ridges visible in dry fruit. Endocarp thin to thick, of sclerified cells arranged perpendicular to the inner mesocarp. Seed 1, testa vascularised with post-chalazal or pachychalazal bundles. Embryo small.