Tree or shrub, dioecious or rarely monoecious. Exudate absent*. Unarmed. Indumentum present, hairs always simple. Stipules free*, simple, unlobed, entire *, not spine-like*, not leaf-like*, without glands. Leaves distributed evenly along stem, alternate, simple, unlobed, base symmetrical, margin glandular-toothed, blade not pellucid-punctate; blade lower surface sparsely glandular; with or without 2–4-glands on lower surface at base; venation pinnate (but sometimes seeming to have 3 strong veins from base); domatia sometimes present; stipel-like appendages sometimes present. Petiole present, sometimes swollen or bent at one or both ends. Inflorescence with axis, male axillary or terminal, spike-like racemes, female terminal, racemose; bracts not leaf-like*, green; in female inflorescences bracteoles 2-glandular at base; pedicels present or 0, articulated or not. Male flowers: almost sessile, pedicels very short, almost 0; sepals 3–4, valvate, partially fused, greenish; petals 0; disc 0; stamens 3–5 (8–10), fused in basal part to form a short column, free above; anther without conspicuous modification, thecae mostly extrorse in bud; pistillode present or 0. Female flowers: calyx 2-glandular, sepals 4, imbricate, free or partially fused, greenish, margins glandular; petals 0; disc 0; ovary locules 3, ovules per locule 1*; styles 3, partially fused, 2-branched (i.e. ultimate divisions per locule 2); styles or stigmas a little flattened, surface papillose; staminodes absent. Fruit dehiscent, smooth, greenish to brown; seed without appendage, covering or membraneous layer*, not fleshy; embryo flat*, not minute*, cotyledons leaf-like*.
An asterisk * indicates a state has been assumed but not yet confirmed.
World Checklist: 1 species: Aparisthmium cordatum.
See: Secco, R. S. (2004) Alchorneae (Euphorbiaceae) (Alchornea, Aparisthmium, Conceveiba), Flora Neotropica Monograph 93. Organization for Flora Neotropica. New York Botanical Garden, Bronx, New York, U.S.A.