5. Gamochaeta argyrinea G. L. Nesom, Sida. 21: 718, figs. 1-4. 2004.
Annuals (winter annuals), 12–40 cm; usually fibrous-rooted, rarely taprooted. Stems decumbent-ascending, closely white-pannose (hairs usually individually evident, seldom forming clothlike indu-ments). Leaves basal and cauline, basal present through flowering, blades oblanceolate to oblanceolate-oblong or oblanceolate-obovate, 1.5–5(–8) cm × 5–12(–18) mm (gradually smaller distally), faces bicolor, abaxial closely white-pannose, adaxial sparsely arachnose (evident at 10×). Heads initially in continuous, cylindric arrays 1.5–5 cm × 10–12 mm (pressed), later sometimes interrupted, 5–18 cm × 10–12 mm (pressed; producing axillary glomerules from proximal nodes). Involucres campanulate, 3–3.5 mm, bases sparsely arachnose. Phyllaries in 4–6 series, outer (tawny-transparent, never dark brown) ovate to ovate-lanceolate, lengths 1/3–4/5 inner, apices acute to acuminate, inner elliptic-oblong to oblong, laminae often purplish tinged (around stereome/lamina junction, otherwise hyaline and slightly brownish), apices truncate-rounded, apiculate (flexing slightly outward in fruit). Florets: bisexual 4–5(–6); all corollas purple- to yellow-brown distally. Cypselae (tan) 0.5–0.6 mm.
Flowering Mar–Jun(–Oct). Roadsides, fields, lawns, open woods, sand or clayey soils, open, disturbed areas; 0–300 m; Ala., Ark., Fla., Ga., Kans., Ky., La., Md., Miss., N.C., Okla., Pa., S.C., Tenn., Tex., Va., W.Va.; West Indies.
Gamochaeta argyrinea has been confused with G. purpurea, which also occurs across the coastal states of eastern United States (G. L. Nesom 2004).