Acer glabrum var. diffusum
Mountain maple
(c) Caleb Catto, some rights reserved (CC BY), uploaded by Caleb Catto · licence
Family: Sapindaceae · Type: Shrub / Tree · Native
Acer glabrum var. diffusum (Mountain maple) is a native California shrub / tree in the Sapindaceae family, recognized by small leathery leaves and high elevation habitat.
Mountain maple is a California native shrub found in the southern High Sierra Nevada, Transverse Ranges, White and Inyo Mountains, and Desert Mountains on dry montane rocky slopes and canyons at elevations of 1,600 to 3,100 meters. Flowering from April to May, this plant produces small greenish-yellow flowers with rounded lobes. Growing as a multi-stemmed shrub 1 to 3 meters tall with spreading branches, it has a distinctive leathery foliage. Its leaves have 2 to 3 rounded lobes, each with 3 to 7 small teeth, and measure approximately 1.4 to 2.8 centimeters long with petioles 0.9 to 2.4 centimeters in length.
Identification and appearance
Key characters: 4 sympatric species; distinguished by small leathery leaves and high elevation habitat
Habitat and range
Habitat: dry montane rocky slopes, canyons
Elevation: 1600-3100 m
California counties: San Bernardino, Inyo, Kern, Riverside, Tulare, Mono, Alpine, Butte, Siskiyou, Plumas, Placer, Tuolumne
Outside California: to central Utah
Bloom period
Acer glabrum var. diffusum blooms Apr-May.
How to tell it apart
vs Platanus: Maple fruits are paired helicopters; sycamore has hanging ball-like seed clusters and peeling bark.; vs Liquidambar: Maple fruits split into two wings; sweetgum has spiky round seed balls and star-shaped leaves with pointed lobes.; vs Quercus: Maple leaves have palmate veins radiating from base; oak leaves have pinnate veins branching from midrib.; vs Fraxinus: Maples have simple lobed leaves; ash has compound leaves with 5-9 separate leaflets arranged feather-like.; vs Morus: Maple fruits are dry winged samaras; mulberry produces fleshy blackberry-like fruits and has milky sap.
Frequently asked questions
Is Acer glabrum var. diffusum native to California?
Yes. Acer glabrum var. diffusum is native to California (recorded as native).
When does Acer glabrum var. diffusum bloom?
Acer glabrum var. diffusum blooms Apr-May.
Where in California does Acer glabrum var. diffusum grow?
Acer glabrum var. diffusum occurs in San Bernardino, Inyo, Kern, Riverside, Tulare, Mono, Alpine, Butte and other counties, at elevations of 1600-3100 m.
What plant family does Acer glabrum var. diffusum belong to?
Acer glabrum var. diffusum is in the Sapindaceae family, genus Acer.
What habitat does Acer glabrum var. diffusum grow in?
Acer glabrum var. diffusum grows in dry montane rocky slopes, canyons.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.