Button Burrweed

Plants mostly 3–15(–30+) cm (high or across), ± villous, glabrescent (sometimes stoloniferous, ± mat-forming). Leaves mostly basal; blades ± obovate to spatulate, 3–8(–15) cm, 2–3-pinnati-palmately lobed. Heads mostly clustered in leaf axils (at ground level), rarely scattered along stems. Involucres 4–8+ mm diam. Pistillate florets (20–)50–100+ in 1–8+ series. Disc florets 2–4+; corollas 1.5–2 mm. Cypselae: bodies oblanceolate to cuneate-oblong, 1.5–2+ mm, wings transversely rugulose or ribbed on proximal ²/3, shoulders not spinose laterally, faces distally villous to pilose, sometimes glabrescent; pappi 0 (persistent stylar sheaths indurate, spinelike, 1.5–3 mm, usually inflexed). 2n = 118 (Punjab).

An introduced weed of S. American origin.

1100-1400 m

Gymnostyles anthemifolia Jussieu, Ann. Mus. Natl. Hist. Nat. 4: 262, plate 61, fig. 1. 1804; Soliva mutisii Kunth

Gymnostyles anthemifolia A. Juss. Ann. Mus. Paris 4: 262
1804.
Soliva anthemidifoUa R. Br.; Less. Syn. Comp. 268. 1832.
A low subacaulescent annual, branched from the base, the branches usually less than 5 cm. long, sometimes almost none, hirsute ; leaves hirsute, 3-6 cm. long, bipinnatifid into linear or linear-oblanceolate, gradually acute, divisions; involucre 8-10 mm. broad; bracts 15-20, lanceolate; corollas of the hermaphrodite flowers pubescent, 3 mm. long; tube slender, gradually tapering into the narrow elongate-funnelform throat; lobes 4; achenes obovate in outline, 3.5 mm. long, 2 mm. wide; body puberulent, narrow; wing thick, transversely reticulate, except the broadly subconic villous apex; beak 2 mm. long.
Type locality; "Australasia" [?].
Distribution: Southern Mexico to Paraguay; adventive in Louisiana and Texas.