Shrubs or trees, 10–70[–150] dm. Leaves imparipinnate (mimosoid in appearance); leaflets [14–]17–35[–40], alternate, elliptic, 8–33 × 3–9 mm, base rounded to oblique. Inflorescences lateral to subterminal, racemes. Flowers: sepals 5; petals 5 or 0; stamens 5, anthers dorsifixed with enlarged connective, thecae parallel; pistils 3-carpellate, 2 lateral carpels sterile, central fertile, in staminate flowers pistils vestigial. Fruits samaras, flattened or recurved, usually hairy; sepals not persistent. Seeds 1, ellipsoid, ± 1/4–1/3 length of samara. x = 8.
Fla., Mexico, West Indies, Central America, South America (Argentina, Bolivia).
Species 6 (1 in the flora).
A chromosome count for Alvaradoa subovata Cronquist of Argentina is 2n = 16 (A. M. Sanso and M. N. Seo 2005). The samara is derived from a dry, indehiscent capsule; the wings are formed from the two lateral, sterile carpels.