Amphipterygium Schiede ex Standl.
Dioecious shrubs or trees with milky exudate. Leaves deciduous, alternate, imparipinnate, trifoliolate, or rarely unifoliolate; leaflets opposite. Inflorescences axillary; male flowers arranged in pendent thyrses, female flowers tightly arranged and subtended by an involucre. Flowers perigynous; calyx 6–8-parted in male flowers, 0 in female flowers; corolla 0; androecium haplostemonous; filaments short; pistillode and staminodes 0; disk 0; carpels 3; styles 3; stigmatic lobes 3–4 per style, revolute; ovule basal. Fruit a samaroid syncarp, 1-locular; exocarp brown; endocarp bony; peduncle much-dilated with tapering margins.
Four to five species in western Mexico south to northwestern Costa Rica. Together with Orthopterygium, this genus is often segregated into the family Julianiaceae, but morphological and molecular data place it well within Anacardiaceae.
Original Publication: Amphipterygium Schiede ex Standl., Contr. U.S. Natl. Herb. 23: 672 (1923)
X. M. C. Figueroa, Ibugana: Boletín IBUG, 13(1): 27-47 (2005), rev.