Trees or occasionally shrubs, deciduous, monoecious. Branchlets with solid pith. Terminal buds subglobose to ovoid, with broad, overlapping scales. Leaves odd-pinnate, rarely simple; leaflets (1-)7-15(-23), margin serrate. Inflorescences terminal on new growth, erect at apex of leafy branchlets, an androgynous panicle of male and female spikes, with mainly lateral spikes male, central spike female but male at apex, or occasionally panicle becoming wholly male when female spike aborts. Flowers entomophilous. Male flowers with an entire bract; bracteoles absent; sepals absent; stamens 4-15, anthers glabrous. Female flowers subtended by an entire bract, ± free from ovary; bracteoles 2, adnate to ovary; sepals 2, adnate to bracteoles; style absent; stigmas carinal, 2-lobed, short, minutely plumose. Fruiting spike short, conelike, erect, with rigid, persistent bracts. Fruit a small, flattened, narrowly 2-winged nutlet, 2-chambered at base. Germination epigeal.