The California flannelbush (Fremontodendron californicum, syn. Fremontia californica Torr.) is a flowering evergreen shrub with fuzzy, flannel-like leaves and colorful blossoms. It bears the alternate common names California fremontia and flannel flower. It is one of two species in genus Fremontodendron, and it is divided into four subspecies. It is found in a few mountainous spots in California, especially in the Sierra Nevada foothills, where it thrives in chalky, sandy, nutritionally-poor soils. It is also found in small, isolated populations in the mountains of central and western Arizona , primarily in the Mazatzal and Superstition Mountains.
The subspecies Pine Hill flannelbush (F. c. decumbens) is a federally-listed endangered species. It is sometimes known by a species name of its own, Fremontodendron decumbens. It can only grow in metal-rich gabbro soil, a red weathered soil of volcanic origin, and requires fire for seed germination. Nearly all of the individuals of this species are found in the Pine Hill Ecological Reserve, but since this reserve is near human habitation, fire is suppressed.
The subspecies F. c. californicum, which is usually called California flannelbush or California slippery elm, is more common and is sometimes cultivated as an ornamental. The flowers are yellow and each petal has an attractive, curved shape that comes to a point. The bark bears a gooey sap that was once used as a topical remedy for mucous membrane irritation and for gastrointestinal upset. However, the hairs covering the leaves are easily brushed off and are a skin and eye irritant.