Contr. U.S. Natl. Herb. 12: 373. 1909.
Stems often tangled among themselves, 3–20 dm. Leaves: petiole 3–25 mm; blade ovate, triangular, or rhombic-orbiculate, 15–60 × 10–45 mm, base obtuse, truncate, or cordate, margins shallowly sinuate, apex usually acute or acuminate, sometimes obtuse or round. Inflorescences: peduncle 4–6 cm; umbel 4–11-flowered; pedicel 3–15 mm. Perianths pale greenish yellow, 3–4 mm, glabrous or with few minute hairs externally near margin of limb. Fruits usually reflexed at tip of pedicel, 7–10 × 1.5–2 mm.
Phenology: Flowering late spring-mid fall.
Habitat: Dry, gravelly areas, often among boulders or shrubs, roadsides
Elevation: (0-)800-1800 m
Ariz., N.Mex., Tex., Mexico, West Indies, Central America, South America
"thin" is not a number."dm" is not declared as a valid unit of measurement for this property.