Annuals or perennials, (2-)10-90(-120+) cm. Stems erect, branched distally or ± throughout. Leaves mostly cauline; opposite or alternate; sessile or subsessile; blades usually 1(-3)-nerved, elliptic, lance-linear, lanceolate, lance-ovate, linear, ovate, rhombic, or rhombic-ovate, margins entire (often revolute), faces hispid or strigose to stigillose, sometimes gland-dotted. Heads radiate, borne singly or in cymiform to paniculiform arrays. Involucres hemispheric or broader, 6-14 mm diam. Phyllaries persistent, 14-25 in ± 2-3 series (mostly lance-linear, herbaceous). Receptacles conic; paleate (paleae tan to brown, ovate to oblong-rectangular, conduplicate). Ray florets 5-15, neuter; corollas yellow (laminae elliptic, oblong, obovate, oval, or ovate). Disc florets 25-50+, bisexual, fertile; corollas yellow, tubes shorter than campanulate throats, lobes 5, triangular (style branches relatively slender, apices acute). Cypselae (black, mottled, or gray-striate) weakly 4-angled, ± obpyramidal (glabrous); pappi 0. x = 8. Heliomeris has often been submerged within Viguiera; herbaceous phyllaries, epappose cypselae, and distinctive chromosome base number provide morphologic and genetic features that correlate with molecular phylogenetic studies to suggest that it be recognized as distinct. A species from granite outcrops of the southeastern United States, Helianthus porteri, shows remarkable morphologic similarity to Heliomeris, but cytologic, crossing, and molecular phylogenetic studies have provided abundant evidence that it is properly placed in Helianthus. W. F. Yates and C. B. Heiser (1979) provided a useful summary of Heliomeris, and their treatment is followed here.