Trees, monoecious. Exudate (from cut stems) present, white. Armed (stem spiny). Indumentum present, hairs simple (multicellular, usually yellowish-brown). Stipules large, free*, simple, unlobed, entire, not spine-like*, not leaf-like*, without glands. Leaves distributed evenly along stem, alternate, simple, unlobed, base symmetrical, margin toothed or almost entire, blade not pellucid-punctate, upper and lower surface without glands (except for those at petiole apex), glands on leaf margin?; venation pinnate; domatia absent*; stipel-like structures absent*. Petiole long, without swellings or bends at base or apex*, upper surface 2-glandular at apex. Inflorescence with axis (at least male part), terminal and axillary, with 1 female flower in axis of or separate from male part, male part with long flowerless stalk below (peduncle), many-flowered section above, flowers densely-set; bracts numerous, without glands, peltate, greenish, initially united into a membraneous, tunica-like sheath; floral buds initially covered by the sheath, later breaking through it; pedicels present, not articulated*. Male flowers: with distinct pedicels, breaking through the sheath when flowering; sepals completely fused into a cup, greenish; petals 0; disc 0; stamens 10–80, filaments long, completely fused into a stout column; anthers in 2 or more sessile whorls around the upper part of the column, without conspicuous modification, thecae extrorse in bud; pistillode absent. Female flowers: with distinct pedicels; sepals 5, partially to completely fused and cup-like, greenish; petals 0; disc 0; ovary locules 5–20, ovules per locule 1; styles completely fused into a large, conspicuous column, stigmas 5–20, entire, flat, united into a large, conspicuous, lobed disc borne at the top of the style column, surface smooth*; staminodes absent. Fruit dehiscent, not sculptured, glabrous, greenish to brown; seed without appendage, covering or membranous layer; embryo flat, not minute, cotyledons leaf-like.
An asterisk * indicates a state has been assumed but not yet confirmed.