Erigeron parishii

Erigeron parishii is native to San Bernardino County and Riverside County in southern California.[3][2] It is a federally-listed threatened species losing habitat to development and the limestone mining industry on the north slope of the San Bernardino Mountains.

Erigeron parishii is a small perennial herb reaching a maximum height of about 30 centimeters (12 inches). The taproot can penetrate the carbonate soils to a depth of 50 cm (19.5 in).[4] Its stem and foliage are covered in silvery-white hairs and most of the leaves are basal and measure 3 to 6 centimeters (1.2 to 2.4 inches) long.[1]

The erect stems have inflorescences of one to ten flower heads, each between one and two centimeters (0.4-0.8 inches) wide. The flower head has a center of golden yellow disc florets and a fringe of up to 55 lavender, pink, or white ray florets.[1]

Erigeron parishii usually grows on limestone substrates, or granite topped with a layer of limestone.[5] It apparently requires very alkaline soils.[4][1]

The same rock that the plant favors is also sought after for human use and limestone mining is the most significant threat to its habitat.[4]

Erigeron parishii has a relatively high genetic diversity for a narrow endemic, a measure that will decrease with the habitat fragmentation that currently threatens it.[6]

• Jepson Manual Treatment — Erigeron parishii
• United States Department of Agriculture Plants Profile: Erigeron parishii
• US Fish & Wildlife Service, Conserving the Nature of America, Local Rare Plants (1997)
• Erigeron parishii — Calphotos Photo gallery, University of California