Flora of North America species comparison

Species 5 (2 in the flora).

See discussion of Filagininae following the tribal description (p. 385).

Micropus species are found mostly in dry, open habitats of Mediterranean climates. In the flora, they are known only from west-draining portions of the Californian Floristic Province and the Willamette Valley in Oregon.

The two North American species constitute Micropus sect. Rhyncholepis Nuttall. Recent European workers (e.g., J. Holub 1998) have included sect. Rhyncholepis in Bombycilaena, leaving M. supinus Linnaeus in a monotypic genus. Based on phylogenetic data (J. D. Morefield 1992), that approach would include in Bombycilaena species ancestral to, and derived from ancestors of, Micropus. I maintain Micropus in its traditional sense here. Micropus and Psilocarphus appear to be monophyletic sister genera derived from near or within Stylocline. A malformed specimen from Monterey County, California, appears to be a sterile hybrid between M. californicus and a species of Psilocarphus.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Varieties 2 (2 in the flora).

Though common and often found on recent disturbances within its range, Micropus californicus does not appear to be particularly invasive or weedy. The mature pistillate paleae, with roughly the profile of a harp or of an inverted lower-case letter “q,” are distinctive. That shape and the accompanying dense, cottony indument of the common variety explain the vernacular names. By contrast, pistillate paleae of M. amphibolus have roughly the profile of a human head wearing a billed cap.

Within the more limited range of var. subvestitus, the two varieties are broadly sympatric, usually in separate populations, occasionally in mixed populations that sometimes include intermediate plants.

(Discussion copyrighted by Flora of North America; reprinted with permission.)