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Neotropical Euphorbiaceae s.l.
Actinostemon
SUMMARY
Trees or shrubs, monoecious. Exudate present. Unarmed*. Glabrous throughout or indumentum present, hairs simple (multicellular, coloured). Stipules free*, simple, unlobed, entire *, not spine-like*, leaf-like or not*. Terminal buds often enclosed by conspicuous large stipules. Leaves distributed evenly along stem, alternate or appearing whorled, simple, unlobed, base symmetrical, margin entire, blade not pellucid-punctate, upper surface without glands, lower surface with glands near base, near margin and/or distributed sparsely throughout blade, lower surface sometimes also whitish; venation pinnate or with 3 distinct veins from base; domatia absent*; stipel-like structures absent*. Petioles short, without swellings or bends at base or apex*, without glands. Inflorescence: buds covered by large, usually conspicuously parallel-veined, sterile scales (bracts?); inflorescence with axis, terminal and/or axillary, raceme- or panicle-like, female flowers few, near base, male flowers above, many, the male part of the inflorescence often falling away later; bracts of side branches small and inconspicuous, glandular or not, floral bracts irregular, small, hair-like or almost 0, with a pair of elliptical glands or glands 0, all bracts green; floral buds initially protected by sterile scales (bracts?); pedicels present, not articulated*. Male flowers: sepals 0 or 3, free, very small, greenish; petals 0; disc 0; stamens about 3–12, free or partially fused; anther without conspicuous modification, thecae extrorse in bud; pistillode absent. Female flowers: pedicel sometimes conspicuously long after flowering; sepals 0 or 3, free, greenish; petals 0; disc 0; ovary locules 3, ovules per locule 1; styles 3, completely fused into a column (stigmas free), or styles 0, stigmas 3, free, entire, not flat*, surface smooth*; staminodes absent. Fruit with short or long-conspicuous pedicel; dehiscent, smooth or horned, very rarely spiny or bristly, glabrous or hairy, greenish to brown; seed with a small caruncle, with no other covering or membranous layer; embryo flat, not minute, cotyledons leaf-like.
An asterisk * indicates a state has been assumed but not yet confirmed.
World Checklist: about 20 spp.
With thanks to Hans-Joachim Esser (Botanische Staatssammlung München) for help with this genus.