|Natural range of 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. It was rare when it was first discovered in 1897 or 1898, when about 40 to 50 plants were counted. When it was federally listed 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." in Wild Boar Gully, an arroyo covered in coastal sage scrub on Catalina. The steep sides of the arroyo contain soils of saussurite gabbro.
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. 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.
The Catalina Island mountain mahogany is threatened by ungulates such as deer, and feral goats and pigs. The goats have been removed from the island, and fencing has been placed to prevent the remaining animals from touching the plants.
This rare species hybridizes with its relative, Cercocarpus betuloides, a situation that may lead to genetic swamping of the rare plant. This hybridization may be made more likely by the animals' disturbance of the habitat. Many of the seedlings and saplings growing today may be hybrids.
- "Comprehensive Report Species - Cercocarpus traskiae". NatureServe. The Nature Conservancy. August 2010. Retrieved January 2011. Check date values in:
- "National Collection of Imperiled Plants - Plant Profile: Cercocarpus traskiae". Center for Plant Conservation, Missouri Botanical Garden, St. Louis, Missouri. March 2010. Archived from the original on 2010-12-15. Retrieved January 2011. Check date values in:
- USFWS. Cercocarpus traskiae Five Year Review. September 2007.
- Rieseberg, L. H. and D. Gerber. (1995). Hybridization in the Catalina Island mountain mahogany (Cercocarpus traskiae): RAPD evidence. Archived September 28, 2010, at the Wayback Machine. Conservation Biology 9:1 199.
- IUCN Red List of Threatened Species: Cercocarpus traskiae; World Conservation Monitoring Centre (1998) . downloaded on 30 January 2011.