Holocarpha virgata is a California endemic restricted to altitudes less than 800 meters. Bioregional distribution includes the Inner North Coast Ranges, north and central Sierra Nevada Foothills, California Central Valley, eastern Central Western California and disjunctively along the central and southern South Coast. Preferred habitats are grasslands.

Also known by the common name Yellowflower tarweed annual herb grows to a height of 20 to 120 centimeters, with branches generally not rising higher than the main stem. Branches are soft-hairy and glandular below, canescent or short-bristly above. The characteristic tarweed resinous Leaves have lower leaf occurrences ranging from six to 15 cm in length and are linear and bristly. Upper leaves are crowded. The inflorescence is spike- or raceme-like, withnorm heads ally sessile. The more or less obconic involucres are five to six mm. Ray flowers have ligules about four to six mm. Disk flowers 9–25; corollas 3.5–4.5 mm; anthers black

United States

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

Plants 20–120 cm.; stems usually notably stipitate-glandular, rarely merely ± resinous distally. Heads borne singly (at ends of branches) or in ± racemiform to spiciform arrays. Involucres ± obconic to campanulate. Phyllaries each bearing 5–20 gland-tipped processes and glabrous or minutely sessile- or stipitate-glandular. Ray florets 3–7. Disc florets 9–25; anthers reddish to dark purple. 2n = 8.

Holocarpha virgata occurs widely in the Great Valley and bordering foothills of the Coast Ranges and Sierra Nevada in northern and central California (subsp. virgata); it is disjunct in southwestern California (e.g., subsp. elongata near San Diego). Different populations are often intersterile and distinguished by chromosomal rearrangements.

Hemizonia virgata A. Gray in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 100. 1859

Isotype for Hemizonia virgata A. Gray in Emory
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Verified from the card file of type specimens
Preparation: Pressed specimen
Collector(s): J. Fremont
Year Collected: 1854
Locality: California, United States, North America

Rounded Global Status Rank: G5 - Secure

United States

Rounded National Status Rank: NNR - Unranked