Plant: tree; to 10 m high, essentially glabrous except for tomentose inner surface of bud scales; young twigs dark purplish-red to reddish-brown, the epidermis of older twigs flaking off in thin whitish sheets; buds covered with two valvate pink to red scales

Leaves: deciduous, suborbicular in outline, 3-7 cm long, 3.5-9 cm wide, palmately 3-lobed (2 additional basal lobes sometimes present) or 3-foliolate, often a mixture of both types present, discolorous, the leaflets, when present, elliptic to subrhombic; apex of leaf and principal lobes or leaflets acute or obtuse; base cordate to obtusely cuneate, the base of leaflets cuneate to acuminate; petiole 1.5-9 cm long; margin coarsely serrate, the several teeth acute to acuminate

INFLORESCENCE: corymbose

Flowers: ca. 5 mm long, ca. 1.5 mm wide at base of perianth, the perianth greenish-yellow, with 10 sublinear segments ca. 4 mm long, the receptacle obconic; inflorescence corymbose, ca. 1.5 cm long, the pedicels 0.2-0.5 cm long

Fruit: samaras 2-2.3 cm long, the wing ca. 1 cm wide

Misc: In conifer forests, especially along streams; 2100-2900 m (7000-9500 ft);; May (retaining fruits until Aug and Sep)

REFERENCES: Landrum, Leslie R. 1995. Aceraceae. J. Ariz. - Nev. Acad. Sci. 29(1): 2, 2-3.

Common Name: Rocky Mountain maple

Duration: Perennial

Nativity: Native

Lifeform: Tree

Wetland Status: FAC

General: Shrubs or trees up to 10 m, with smooth, gray bark.

Leaves: Leaves bright green, thin, glabrous, and palmately divided, with deeply-toothed margins, coarsely serrate, 3-7 cm long, 3.5-9 cm wide, on petiole 1.5-9 cm long.

Flowers: Corymbose clusters of bright green flowers about 1.5 cm long, flowers about 5 mm long, 1.5 mm wide at base, on pedicels 2-5 mm long.

Fruits: Fruit a winged samara, having 2 wings, pinkish-rose when young, turning to white or light tan when mature, about 2 cm long and about 1 cm wide.

Ecology: Found in deep, rich soils in coniferous forests from 7,000-9,000 ft (2134-2743 m); flowers May-June.

Notes: There are 3 reported varieties in Arizona, differentiated mostly by the location in which they occur. Landrum 1995 suggest most populations are transitional between var. glabrum and var. neomexicanum, var. diffusum is the third variety and is found in northwest Arizona.

Ethnobotany: Decoction of bark taken as a cathartic, to reduce nausea, infusion of branches taken for swelling, to heal women's insides, and snakebites. Dried leaves used to spice stored meat. Wood used for buildings, snowshoes, cradles, bows, and other tools.

Etymology: Acer is the classical Latin name for the maple genus, glabrum means smooth or hairless.

Synonyms: None

Editor: LCrumbacher, 2011