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Shrubs or subshrubs, monoecious, without stinging hairs or prickles. Leaves alternate, in spirals (to distichous) or (sub)opposite; stipules free; blade pinnately veined to tri(pli)nerved. Inflorescences bisexual (or unisexual?), (sub)sessile, (sub)capitate glomerules with (sub)sessile flowers. Staminate flowers: tepals 3, basally connate; stamens 3. Pistillate flowers: perianth tubular with a 2-toothed apex; stigma filiform, persistent. Achene enclosed by a dry fruiting perianth.


Guianas present, Neotropics present, Pantropical, extending to temperate regions present
Pantropical, extending to temperate regions, 60-80 species; in the Neotropics 8-10 species; in the Guianas one or possibly two species.


Growth rings faint or absent. Vessels diffuse, solitary and in radial multiples of 2-4, round to oval, 15-20 per sq. mm, diameter 70-130 μm. Vessel-member length: 240-525 μm. Perforations simple. Intervascular pits alternate, polygonal, 9-12 μm. Vessel-ray and vessel-parenchyma pits as the intervascular pits. Thin-walled tyloses present or absent.
Rays uniseriate and 3-5 seriate (50-120 μm wide), 4-6 per mm, up to several mm high. Uniseriate rays occasionally present, composed of square and upright cells. Multiseriate rays composed of square and upright cells, often containing druses.
Parenchyma scarce, paratracheal, vasicentric. Strands of 2-4 cells.
Fibres non-septate, lumen 15-30 μm, walls 4-6 μm. Pits simple, on the radial and tangential walls. Length: 665-1745 μm.


No material available from the Guianas. Based on Bonsen & ter Welle (1984): B. cylindrica (Equador), B. ramiflora (Dominica).