Big Tarweed

Blepharizonia plumosa is found in the eastern San Francisco Bay area and northwestern San Joaquin Valley. Northern and southern populations appear to be evolutionarily divergent and may warrant treatment as distinct taxa (B. G. Baldwin et al. 2001).

Herbage gray-green, sparsely, if at all, stipitate-glandular, usually with scattered tack-glands as well. Heads usually in spiciform-paniculiform arrays (branches often arched-ascending). Involu-cres usually ± canescent (sometimes also with scattered, longer, glandless hairs), usually with scattered tack-glands as well. Disc pappi 1.5–3 mm. 2n = 28.

Calycadenia plumosa Kellogg, Proc. Calif. Acad. Sci. 5: 49. 1873; Hemizonia plumosa (Kellogg) A. Gray