Cercocarpus traskiae

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,[2] found in Wild Boar Gully, an arroyo covered in coastal sage scrub on Catalina Island.[3] The steep sides of the arroyo contain soils of saussurite gabbro.[2][3]

It was rare when it was first discovered by Blanche Trask in 1897[4] or 1898,[2] when about 40[4] to 50[2] plants were counted.[3]

When it was federally listed as an endangered species, in 1996, there were only six mature plants remaining.[2] It has been called "one of the rarest shrubs in the continental United States"[4] and "one of the rarest trees in North America."[3]

Cercocarpus traskiae is a large shrub or tree that grows up to 8 meters 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.[5] The inflorescence is a cluster of up to 10 flowers which do not have petals. Plants do not always flower each year.[3]

While there are sometimes many seedlings noted, the seedling survival rate and rate of recruitment are quite low.[3] 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.[3]

The Catalina Island mountain mahogany is threatened by ungulates such as deer, and feral goats and pigs.[3] The goats have been removed from the island, and fencing has been placed to prevent the remaining animals from touching the plants.[3]

This rare species hybridizes with its relative, Cercocarpus betuloides, a situation that may lead to genetic swamping of the rare plant.[5] This hybridization may be made more likely by the animals' disturbance of the habitat.[3] Many of the seedlings and saplings growing today may be hybrids.[3]

The population of pure Cercocarpus traskiae is not increasing and the species is entirely dependent on human intervention today.[3][1]

• Chaparral
• California chaparral and woodlands

• Calflora: Cercocarpus traskiae (Catalina Island mountain mahogany)
• Jepson Manual eFlora (TJM2) treatment of Cercocarpus traskiae
• UC Photos gallery — Cercocarpus traskiae