Acer glabrum is a small tree growing to 6–9 metres (20–30 feet) tall, exceptionally 12 m (39 ft), with a trunk around 13 centimetres (5 inches) in diameter, exceptionally around 25 cm (10 in).[4] The leaves are 2–13 cm (3⁄4–5 in) broad, three-lobed (rarely five-lobed),[4] variable in the depth of lobing, occasionally so deeply lobed as to be divided into three leaflets; the lobes have an acute apex and a coarsely serrated margin. The flowers are produced in corymbs of five to ten, yellowish-green, at the same time as the new leaves in spring. The fruit is a samara or winged seed, which develops in fused pairs at an angle of less than 45° when mature, though some varieties spread out to 90°.[4][5][6]
Varieties
There are four to six varieties, some of them treated by some authors at the higher rank of subspecies:[3][6][7]
Acer glabrum var. glabrum (syn. subsp. glabrum; Rocky Mountain maple)– Rocky Mountains, Montana to New Mexico
Acer glabrum var. douglasii (Hook.) Dippel (syn. subsp. douglasii (Hook.) Wesm.; Douglas maple, also incorrectly vine maple[8]) – Alaska south to Washington and Idaho
Acer glabrum var. greenei Keller (Greene's maple) – endemic-central California
Acer glabrum var. neomexicanum (Greene) Kearney & Peebles (syn. subsp. neomexicanum (Greene) A.E.Murray; New Mexico maple) – New Mexico
Acer glabrum var. torreyi (Greene) Smiley (syn. subsp. torreyi (Greene) A.E.Murray; Torrey maple) – endemic-Northern California
It tends to be found in brush fields arising from fire-disturbed sites. Conifers tend to replace it in well-forested areas.[4] The foliage is browsed by game animals (especially deer and elk in winter), cattle, and sheep.[4][10]
Uses
Native Americans utilized the strong stems for snowshoe frames, bows, and other applications.[4] Some Plateau Indian tribes drink an infusion of Douglas maple as a treatment for diarrhea.[11]RamahNavajo use an infusion of the glabrum variety for swellings, and also as a "life medicine", or panacea.[12][13]