Heterotheca villosa var. scabra

Heterotheca villosa var. scabra (A. Eastwood) Semple is the southwestern less-hairy, more glandular race of the species.  The upper stem leaves are usually narrowly deltoid-lanceolate but sometimes narrowly ovate. Chrysopsis viscida A. Gray ssp. cinerascens S.F. Blake, Heterotheca horrida (Rydb.) Harms ssp. cinerascens (S.F. Blake) Semple are synonyms. The variety hybridizes with var. nana and var. minor in areas where the ranges overlap. It often grows in the same habitats as the rare H. jonesii in southern Utah. Var. scabra primarily grows in Utah, Nevada and Arizona.

Nesom (2006, 2020) treated the variety in part as Het. polothrix Nesom which has distinctly green leaves that are prominently sessile-glandular with reduced numbers of hairs, and heads that tend to be solitary on peduncles with few reduced bracts, and glandular to eglandular to mostly eglandular phyllaries. The range includes only the eastern portion of the range of var. scabra shown below (Semple 1996) and includes SE Utah and N and E Arizona and adjacent Colorado and New Mexico. Nesom (2020) described Het. cinerascens Nesom which has completely glabrous or minutely glandular and resinous-viscid phyllaries, closely spaced, often overlapping, densely sessile-glandular stem leaves and occurs in the western portion of the range of var. scabra that includes W Utah and adjacent Idaho, NW Arizona and most of Nevada. Nesom (2020) described a narrow endemic third species Het. excelsior Nesom from Excelcior Canyon,.Clark Co. Nevada. This third species is distinguished by having long, unbranched, eglandular, and loosely strigose stems, gradually reduced leaves, and relatively small heads compared to his other two new species.

Last revised 8 May 2025 by J.C. Semple

© 2025 J.C. Semple, including all photographs unless otherwise indicated