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FNA | Family List | FNA Vol. 21 | Asteraceae

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.

1 Margins of all leaves entire (margins and veins bearing straight, multicellular hairs 2–3+ mm); cypselae 4–5 mm   3 Psathyrotes pilifera
+ Margins of at least some leaves toothed (faces hairy, hairs not 2–3+ mm); cypselae 1.5–3.5 mm   (2)
2 (1) Plants lanate and furfuraceous; outer phyllaries spatulate to obovate, tips squarrose to reflexed; florets 16–32; pappi of 120–140 bristles   1 Psathyrotes ramosissima
+ Plants sparsely tomentose and furfuraceous; outer phyllaries lance-linear, tips erect; florets 10–20; pappi of 35–50 bristles   2 Psathyrotes annua

Lower Taxa


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