380. Psathyrotes A. Gray, Smithsonian Contr. Knowl. 5(6): 100. 1853.
[Greek psathyros, brittle, fragile, looseness; allusion unclear]
John L. Strother
Bulbostylis de Candolle sect. Psathyrotus Nuttall, Proc. Acad. Nat. Sci. Philadelphia 4: 22. 1848
Annuals or perennials, 5–40+ cm. Stems erect or spreading, usually much branched. Leaves basal and cauline; alternate, petiolate; blades rounded-deltate, reniform, rounded-rhombic, or suborbiculate, margins toothed or entire, faces usually lanate, pilose, or tomentose, sometimes glandular-pubescent and/or furfuraceous as well. Heads discoid, borne singly. Involucres campanulate, cylindric, or turbinate, 3–6+ mm diam. Phyllaries falling or persistent, 8–24 in 2 (contrasting) series (distinct, lance-linear, lanceolate, obovate, or spatulate, tips erect or reflexed to squarrose). Receptacles flat to convex, smooth or ± pitted, epaleate. Ray florets 0. Disc florets bisexual, fertile; corollas yellowish, tubes much shorter than cylindric throats, lobes 5, erect, deltate (style-branch apices rounded-truncate). Cypselae cylindro-fusiform to obpyramidal; pappi of 35–150 distinct or basally connate bristles in 1–4 series. x = 17.
Species 3 (3 in the flora): sw United States, nw Mexico.
Strother, J. L. and G. E. Pilz. 1975. Taxonomy of Psathyrotes (Compositae: Senecioneae). Madroño 23: 24–40.