Herbs, annual; taproot slender. Stems arising directly from the root, spreading to decumbent or prostrate, solid, not fistulose or disarticulating into ringlike segments, pubescent or glabrous. Leaves usually persistent through anthesis, basal and cauline, opposite; petiole present; blade broadly elliptic or round to reniform, becoming linear, margins entire, awn-tipped at proximal nodes. Inflorescences terminal, cymose; branches dichotomous, not brittle or disarticulating into segments, round, usually glabrous; bracts 2, distinct, somewhat leaflike and seemingly succulent, mucronate, pubescent to glabrate. Peduncles absent. Involucral bracts in 1 whorl of 5, distinct, narrowly lanceolate, awn-tipped. Flowers (6-)9-15 per involucral cluster at any single time during anthesis; perianth yellow, broadly campanulate when open, narrowly urceolate when closed, woolly-tomentose abaxially; tepals 6, connate proximally, monomorphic, entire apically; stamens 9; filaments basally adnate, glabrous; anthers yellow, ovate. Achenes included, light brown, not winged, 3-gonous, glabrous. Seeds: embryo curved.
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