Catalina Island Mountain Mahogany

Cercocarpus traskiae is a large shrub or tree that grows up to 8 meters (26 ft) in height. The leaves have thick, leathery oval blades with serrated edges and woolly-haired undersides. The leathery, woolly texture of the leaves distinguishes it from other Cercocarpus. The inflorescence is a cluster of up to 10 flowers which do not have petals. Plants do not always flower each year. While there are sometimes many seedlings noted, the seedling survival rate and rate of recruitment are quite low. As of 2007, there are only seven adult trees capable of reproduction, all located in Wild Boar Gully, and most of these are very old.

It is endemic to Catalina Island, one of the southern Channel Islands in Los Angeles County, California. It is known from just a single population, found in Wild Boar Gully, an arroyo covered in coastal sage scrub on Catalina Island. The steep sides of the arroyo contain soils of saussurite gabbro. It was rare at the time of its discovery by Blanche Trask in 1897 or 1898, when about 40 to 50 plants were counted. When it was proposed for federal listing as an endangered species, in 1996, there were only six mature plants remaining. It has been called "one of the rarest shrubs in the continental United States" and "one of the rarest trees in North America."