Dichapetalum

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Dichapetalum

Description

Small trees, shrubs or lianas. Leaves petiolate. Inflorescences axillary or adnate to petiole, branched cymose or corymbose panicles with long peduncles. Flowers hermaphrodite, polygamous or dioecious, actinomorphic; bracts small; receptacle usually convex or subplanate; sepals 5, imbricate, free, or connate at base; petals 5, free to base, alternate with sepals, usually bicucullate and 2-lobed at apex, margins of lobes inflexed and sometimes enveloping anthers; stamens 5, equal, free, all fertile in male and hermaphrodite flowers, filaments usually free, rarely connate at base only, anthers broadly oblong, introrse; disk usually consisting of 5 hypogynous glands opposite to petals, glands entire, shallowly lobed, free or united; ovary globose, 2-3-locular with 2 ovules in each locule, styles 1-3, free or connate almost to apex, rudimentary pistil present in male flowers. Fruits dry indehiscent drupes, 1-3-locular, usually with 1 seed in each loculus, epicarp pubescent.

Distribution

Africa: present Amazonian Brazil: present Guianas: present New World: present Northern America: Southern America:, Peru (Peru present) lowland tropics in Malesia: present tropical and southern Africa: present
Throughout the lowland tropics in Malesia, tropical and southern Africa, and in the New World from Mexico to Peru and Amazonian Brazil, but not in the Caribbean (most diverse and abundant in Africa); 3 of the 20 Neotropical species occur in the Guianas.

Etymology

The genus is named for the petals that are divided often in 2 cucullate lobes.

Wood

Growth rings indistinct or absent.
Vessels diffuse, mainly solitary, sometimes paired, 8-25 (10.5) per mm², circular or with flattened contact faces when paired, 49-284 (159) μm wide. Perforation plates simple. Intervessel pits and vessel-ray pits alternate with slit-like apertures; vessel-ray pits with distinct borders.
Rays uniseriate and multiseriate (up to 23), 3-8 per mm. Uniseriate rays composed of generally upright cells with some square to upright cells. Multiseriate rays heterogeneous composed predominantly of procumbent and square body ray cells and 1-10 (rarely more) rows of square to upright marginal cells. Multiseriate rays 32-483 (98) μm wide and from 188 μm to several millimetres high (excluding marginal wings). Sheath cells present. Prismatic crystals abundant in the ray cells.
Axial parenchyma mainly aliform (lozenge-aliform and winged aliform), but also diffuse and diffuse in aggregate, and 5-8 cells per strand. Ground tissue of non-septate fibres with thin-to-thick walls and abundant simple to minutely bordered pits on both the radial and tangential walls.

Notes

Gelatinous fibres have been observed in young wood (Prance 1972).