Bol. Soc. Bot. México 35: 25, fig. 1. 1975.
Shrubs [herbs]. Stems usually erect, hairy, not viscid. Leaves: stipules persistent, filiform, sometimes absent; blade ovate to ovatelanceolate, not dissected or parted, base cordate, margins coarsely crenate. Inflorescences axillary, solitary flowers or 2–4-flowered clusters; involucel absent. Flowers: calyx not accrescent, not inflated, ca. 1/2-divided, shorter than mature fruit, lobes unribbed, lanceolate to ovate; corolla blue-violet [bluish lavender, white, or yellow]; staminal column included; style 8–10 [–16] -branched; stigmas capitate. Fruits schizocarps, erect or semipendent, inflated, disciform, prominently lobed, papery, minutely tomentose; mericarps 8–10 [–16], 2-celled, without dorsal spur, apex rounded, proximal cell indehiscent, enclosing 1 seed (each seed covered by endoglossum), distal cell dehiscent, empty (by ovule abortion), unwinged. Seeds 1 per mericarp, subglabrous to sparsely hairy. x = 16.
Tex., n Mexico, n South America (w Venezuela)
Species 5 (1 in the flora).