Santa Catalina Island
With an area of 75 square miles, Santa Catalina Island is the third-largest island in the entire chain and the largest of the Southern Channel Islands. It is situated 20 miles south-southwest of the Palos Verdes peninsula, which is the closest point on the mainland. San Clemente Island, Catalina’s closest island neighbor, is located 21 miles further south.
The flora of Catalina Island includes about 430 native taxa and 220 non-native taxa. The natural distributions of at least 29 of the island’s native taxa are restricted to two or more of the California islands; 9 plant taxa are found only on Catalina Island.
The nine plant taxa found only on Santa Catalina Island:
- Arctostaphylos catalinae (Catalina Island manzanita)
- Cercocarpus traskiae (Catalina Island mountain mahogany)
- Dudleya virens subsp. hassei (Catalina Island live-forever)
- Eriodictyon traskiae subsp. traskiae (Trask’s yerba santa)
- Eriogonum giganteum subsp. giganteum (St. Catherine’s lace)
- Galium catalinense subsp. catalinense (Catalina Island bedstraw)
- Lyonothamnus floribundus subsp. floribundus (Catalina Island ironwood)
- Malacothamnus fasciculatus var. catalinensis (Catalina Island bush-mallow)
- Mimulus traskiae (Catalina Island monkeyflower)
One additional plant (Solanum wallacei) may also be restricted to Santa Catalina Island but its taxonomic relationships need further study.
Catalina Island ecosystems have been altered by more than a century of disturbance by non-native animals (bison, deer, goats, and pigs) that have been detrimental to the native flora.
The following insular endemics are now presumed to be extinct on the island:
- Lycium brevipes var. hassei (Catalina Island desert-thorn)-previously known from Catalina (the last known plant at Avalon was destroyed in 1908 “to make way for buildings”) and from San Clemente (last seen there in 1936).
- Mimulus traskiae (Catalina Island monkeyflower)-known only from a collection made on Catalina in 1901.