Plant: tree; to ca. 12 m high, mainly glabrous to subglabrous except for finely pubescent lower leaf surfaces and young growth; young twigs yellowish-brown, soon becoming chestnut-brown and essentially glabrous; buds at maturity with 3 or 4 series of dark brown, imbricate scales, these pubescent within, elongating when buds break Leaves: suborbicular in outline, palmately 3-lobed (2 additional basal lobes sometimes present), 3-8.5 cm long, 4-12 cm wide, discolorous, the major lobes in turn with up to ca. 5 weak lobes or teeth; apex of leaf and lateral lobes bluntly acute; base cordate to subcordate; petiole glabrous or pubescent distally; margin sinuate to irregularly dentate or lobed Inflorescence: inflorescence corymbose Flowers: to ca. 10 mm long, 1.5-3 mm wide at base of perianth, the usually cup-like perianth greenish-yellow, ca. 5 mm long, sometimes splitting to base, the receptacle truncate to obconic, the perianth margin sinuate to shallowly lobed; the pedicel 1-5 cm long Fruit: samaras 2.2-5 cm long, the wing 0.7-1.5 cm wide Misc: In conifer forests or in wet areas in oak forests; 1350-2600 m (4500-8500 ft); Apr-May (retaining fruits until about Sep) REFERENCES: Landrum, Leslie R. 1995. Aceraceae. J. Ariz. – Nev. Acad. Sci. 29(1): 2, 2-3.