Carpet Burrweed

Plants 2–5(–15+) cm (high or across), ± strigillose to villous (stems procumbent, rooting at nodes). Leaves basal and cauline, blades ± spatulate, 1–2(–3) cm, 1(–2)-pinnati-palmately lobed. Heads mostly scattered along stems. Involucres 3–6(–8) mm diam. Pistillate florets (20–)40–60+ in 2–4+ series. Disc florets 4–6+; corollas 1.5–2 mm. Cypselae: bodies oblanceolate to oblong-cuneate, 1.8–2.2 mm, wings transversely rugulose or ribbed on proximal ⁹/10, shoulders ± spinose laterally, faces distally villous to pilose or arachnose; pappi 0 (persistent stylar sheaths indurate, spinelike, 0.8–1.5 mm, usually inflexed). 2n = ca. 114 (as S. nasturtifolia).

Hippia stolonifera Brotero, Phytogr. Lusitan. Select., no. 14. 1801; Gymnostyles nasturtifolia Jussieu; G. stolonifera (Brotero) Tutin; Soliva nasturtifolia (Jussieu) de Candolle

Gymnostyles nasturtiifolia A. Juss. Ann. Mus. Paris 4: 262
1804.
Soliva naslurliifolia DC. Prodr. 6: 142. 1837. Soliva urbica Philippi, Linnaea 29: 7. 1857.
A dwarf annual, subacaulescent, producing offsets; leaves 1-3 cm. long, sparingly pubescent, pinnatifid, with 7-9 oblanceolate divisions; involucre 4-6 mm. broad; bracts 12-18, linear or linearlanceolate, sparingly pubescent; hermaphrodite flowers very few; corolla villous, 2.5 mm. long; tube gradually tapering into the elongatetrumpet-shaped throat; achenes cuneate in outline, 2.5-3 mm. long, nearly 2 mm. wide; body puberulent; wing transversely reticulate to the truncate apex, which has acute shoulders; beak fully 1.5 mm. long.
Type locality: Buenos Aires.
Distribution: North Carolina to Florida; Louisiana; naturalized from South America.