Psathyrotes

A. Gray

Smithsonian Contr. Knowl. 5(6): 100. 1853. 1853

Etymology: Greek psathyros, brittle, fragile, looseness allusion unclear
Basionyms: Bulbostylis sect. Psathyrotus Nuttall Proc. Acad. Nat. Sci. Philadelphia 4: 22. 1848
Treatment appears in FNA Volume 21. Treatment on page 416. Mentioned on page 415, 456.

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.

Distribution

sw United States, nw Mexico.

Discussion

Species 3 (3 in the flora).

Key

1 Margins of all leaves entire (margins and veins bearing straight, multicellular hairs 2–3+ mm); cypselae 4–5 mm Psathyrotes pilifera
1 Margins of at least some leaves toothed (faces hairy, hairs not 2–3+ mm); cypselae 1.5–3.5 mm > 2
2 Plants lanate and furfuraceous; outer phyllaries spatulate to obovate, tips squarrose to reflexed; florets 16–32; pappi of 120–140 bristles Psathyrotes ramosissima
2 Plants sparsely tomentose and furfuraceous; outer phyllaries lance-linear, tips erect; florets 10–20; pappi of 35–50 bristles Psathyrotes annua
... more about "Psathyrotes"
John L. Strother +
A. Gray +
Bulbostylis sect. Psathyrotus +
sw United States +  and nw Mexico. +
Greek psathyros, brittle, fragile, looseness +  and allusion unclear +
Smithsonian Contr. Knowl. +
strother1975a +
Compositae +
Psathyrotes +
Asteraceae (tribe Heliantheae) subtribe Gaillardiinae +