Eucycla Nuttall, Proc. Acad. Nat. Sci. Philadelphia 4: 16. 1848

Shrubs, subshrubs, or herbs, sometimes nearly arborescent, perennial, glabrous or pubescent, rarely glandular; taproot woody. Stems matted to spreading, decumbent, or erect, infrequently absent, with or without persistent leaf bases, glabrous or variously pubescent or glandular; caudex stems woody, tightly compact to spreading and at or just below surface, or spreading to erect and above surface; aerial flowering stems arising at nodes of caudex branches, at distal nodes of aerial branches, or directly from root, prostrate or decumbent to erect, slender to stout and usually solid, infrequently slightly to distinctly fistulose and hollow. Leaves basal, sometimes in rosettes, sometimes sheathing up stems, cauline, or basal and cauline, 1 per node or fasciculate on flowering stems, at tips of dwarf branches, or on exposed woody caudices, usually persistent, occasionally persistent through growing season or longer, rarely quickly deciduous; blade glabrous or floccose to tomentose, occasionally also glandular. Inflorescences cymose, cymose-umbellate, umbellate, virgate, or racemose, mostly spreading and open to diffuse, sometimes dense, congested, or compact, sometimes reduced and in subumbellate, subcapitate, or capitate heads or reduced to a single terminal involucre; branches open to diffuse, spreading to erect, usually dichotomously branched except for initial trichotomous node, round and smooth, rarely grooved, angled, or ridged, tomentose to floccose or glabrous, occasionally lanate or glandular, rarely scabrellous; bracts usually 3, connate basally, usually scalelike, sometimes semileaflike or leaflike. Peduncles absent or erect, usually stout. Involucres 1-8 or more per cluster, narrowly turbinate to campanulate; teeth (3-)5-6(-10), erect or occasionally spreading, apex acute to obtuse or rounded. Flowers bisexual or, infrequently, unisexual, not attenuate at base, without stipelike base (except for slightly winged stipelike bases in E. saxatile and E. crocatum); perianth various shades of white, yellow, pink, or red, glabrous, glandular, or variously pubescent abaxially, usually glabrous adaxially except for minute glands and a few scattered hairs; tepals connate only basally or in proximal 2, monomorphic or dimorphic; stamens usually exserted, sometimes included; filaments variously pubescent but usually pilose proximally, infrequently glabrous. Achenes light to dark brown, not winged (but nearly so in E. saxatile), 3-gonous, glabrous, occasionally with minutely papillate beak. Seeds: embryo curved.

Species 107 (101 in the flora): w North America (including nw Mexico), mainly arid regions.

Species of subg. Eucycla not accounted for in this treatment are: Eriogonum encelioides Reveal & C. A. Hanson, E. fastigiatum Parry, E. molle Greene, E. orcuttianum S. Watson, E. pondii Greene, and E. zapatoense Moran. All are native to Baja California, Mexico.

The keys to species for subg. Eucycla are broken into geographic regions to aid in identification. They are: California (key 1, p. 225); British Columbia, Idaho, Oregon, and Washington (key 2, p. 228); Nevada and Utah (key 3, p. 231); Arizona and New Mexico (key 4, p. 237); Alberta, Colorado, Montana, and Wyoming (key 5, p. 239); and Manitoba, Saskatchewan, Great Plains states, and Texas (key 6, p. 242).