Deinandra conjugens

Deinandra conjugens (syn. Hemizonia conjugens) is a rare species of flowering plant in the aster family known by the common names Otay tarplant and Otay tarweed. It is native to a small section of far northern Baja California in Mexico, its range extending north into San Diego County, California, in the United States. One isolated population has been reported from the hills east of Cayucos in San Luis Obispo County. Deinandra conjugens is threatened by habitat destruction and degradation. It was federally listed as a threatened species in 1998. Deinandra conjugens grows in clay soils in several types of habitat, including grassland and maritime and inland coastal sage scrub. It tolerates some disturbance in its habitat, and low levels of grazing and road maintenance activities such as mowing are probably beneficial. Most of the known occurrences of Deinandra conjugens are in San Diego County in the United States. Most of them are located in the southern part of the county in areas such as Otay Mesa and Proctor Valley. The city of San Diego has a conservation plan for this species and monitors it. There are about 34 to 37 occurrences remaining; some known occurrences are thought to have been extirpated since the plant was federally listed. The region in which the plant lives is heavily impacted by development and other processes and exists now in a fragmented state. 70% of the plant’s habitat within its range has been destroyed. Much of the territory previously threatened by development has been conserved within a number of nature reserves. Many are protected under a San Diego county ordinance.