Holocarpha virgata is a species of flowering plant in the family Asteraceae known by the common names yellowflower tarweed, pitgland tarweed, and narrow tarplant.CalFlora taxon report, University of California: Holocarpha virgata
Distribution Holocarpha virgata is endemic to California, where it is most common in the San Joaquin Valley and Sacramento Valley of the Central Valley, and adjacent foothills of the Inner Coast Ranges and Sierra Nevada (U.S.).CalFlora: Distribution map . accessed 11.14.2013 There are additional populations in foothills of the Peninsular Ranges in San Diego County, western Riverside County, and Orange County.Flora of North America: Holocarpha virgata
Description Holocarpha virgata is an annual herb producing an erect stem to over tall. It has many branches and is lined with oily glands and hairs. The linear leaves are up to long near the base of the plant and those along the stem are much smaller.
The inflorescence is made up of several short branches lined densely in small, thick, green bracts. The bracts are just a few millimeters long and are tipped with glands. At the ends of the branches are flower heads, each lined with phyllaries which are covered in knobby resin glands. Each head contains 9-25 disc florets which are yellow with black or purplish anthers. The head has a fringe of 3-7 yellow ray florets which often have lobed tips.
Subspecies Holocarpha virgata subsp. elongata D. D. Keck - San Diego County, western Riverside County, and Orange County Holocarpha virgata subsp. virgata - Central Valley, etc.
References
External links Jepson Manual Treatment: Holocarpha virgata
United States Department of Agriculture Plants Profile for Holocarpha virgata Holocarpha virgata — Calphotos Photo gallery, University of California