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Herbs, monoecious, with stinging and/or glandular hairs. Leaves spirally arranged to distichous; stipules connate; blade pinnately veined. Inflorescences bisexual, ± paniculate, with the flowers in loose glomerules. Staminate flowers: tepals (4 or) 5, connate; stamens (4 or) 5. Pistillate flowers: tepals 4, unequal, basally connate; stigma tongue-shaped, persistent on the hooked apex of the fruit. Achene not enclosed by the perianth.


Guianas present, Neotropics present, Pantropical present
Pantropical, 23 species; in the Neotropics 3 species, one of them in the Guianas.


Growth rings faint or absent. Vessels diffuse, solitary and in radial multiples and irregular clusters of 2-4, round to oval, 2-10 per sq. mm, diameter 120-270 μm. Vessel-member length: 300-460 μm. Perforations simple. Intervascular pits alternate, round or polygonal, 9-15 μm. Vessel- ray and vessel-parenchyma pits as the intervascular pits. Thin-walled tyloses present or absent.
Rays multiseriate, 3-10 cells (50-225 μm) wide, 1-4 per mm. Heterogeneous, composed of square and upright cells, up to several mm high, or composed of marginal rows of square and upright cells and a central part composed of procumbent cells and up to 600-1940 μm high (in total). Sometimes partly unlignified.
Parenchyma paratracheal as vasicentric rings. Strands of 2-4 cells. Apotracheal parenchyma unlignified, occuring as islands or bands in transverse sections, containing rhaphides and sometimes styloids and vitreous silica.
Fibres non-septate, lumen 18-24 μm, walls 3-4 μm. Pits simple, on the radial and tangential walls. The fibres are storied. Length: 825-1020 μm.


No material available from the Guianas. Based on Bonsen & ter Welle (1984).