Trees or shrubs, dioecious. Exudate absent. Unarmed. Indumentum present, hairs simple. Stipules free, simple, unlobed, entire, not spine-like, not leaf-like, without glands. Leaves distributed evenly along stem, alternate, simple, unlobed, never peltate, base symmetrical, gradually narrowed into the petiole, margin entire, blade not pellucid-punctate, leaf glands absent*; venation pinnate; domatia absent; stipel-like appendages absent. Petiole present, channelled or 2-winged above, without swellings or bends at base or apex, without glands, glabrous. Inflorescence without axis, axillary, flowers in small clusters; bracts not glandular, not leaf-like, green; pedicels present, not articulated. Male flowers: sepals 5, rarely 4 or 6, imbricate, free or partially fused, not enlarged, persistent, greenish; petals 5 (rarely 4 or 6), not valvate*, sometimes imbricate, free, glabrous; disc surrounding the staminal whorl (extrastaminal), annular (lobed); stamens 5 (rarely 4 or 6), free or partially fused; anther in bud erect; pistillode present. Female flowers: sepals 5, rarely 4 or 6, imbricate, free or partially fused, not enlarged, persistent, greenish; petals 5 (rarely 4 or 6), not valvate*, sometimes imbricate, free, glabrous; disc surrounding the ovary, annular (lobed); ovary locules 3, ovules per locule 2; styles 3, free, 2-branched (i.e. each style divided, ultimate divisions per locule 2), styles or stigmas not flat, surface smooth; staminodes present or absent. Fruit explosively dehiscent, 3-, rarely 4-lobed, unsculptured, glabrous, greenish to brown, perianth caducous; seed without appendage, covering or membranous layer*, not fleshy; embryo flat, not minute, cotyledons leaf-like.
An asterisk * indicates a state has been assumed but not yet confirmed.
World Checklist: 4 spp.
Currently our Key to Genera of Euphorbiaceae s.l., Salicaceae and Achariaceae might confuse Savia with Heterosavia, especially the male plants. Molecular work has shown the two genera to be distinct, but morphological differences (that can be seen by eye, or low magnification) are slight.
See: Hoffmann, P. (2008) Revision of Heterosavia, stat. nov., with notes on Gonatogyne and Savia (Phyllanthaceae). Brittonia 60(2): pp. 136–166.