Eriogonum subg. Clastomyelon
J. Wash. Acad. Sci. 26: 304. 1936.
Herbs, erect, herbaceous, polycarpic perennials, glabrous; taproot woody. Stems erect, without persistent leaf bases, glabrous; caudex absent; aerial flowering stems erect, stout, solid or partially hollow, slightly fistulose, jointed basally and disarticulating into ringlike segments, arising directly from the root. Leaves persistent or marcescent, basal, 1 per node; blade pilose. Inflorescences terminal, subspicate, compact; branches racemose distally, disarticulating into ringlike segments, round and smooth, sparsely pilose or glabrous; bracts 3–5, connate basally, scalelike or semileaflike. Peduncles absent. Involucres 1 per node, not appressed to inflorescence branches, campanulate; teeth 5, erect to spreading, apex acute. Flowers not attenuate at base, without stipelike base; perianth yellow to reddish yellow, hispid abaxially, glabrous adaxially; tepals connate proximally 1/4–1/3 their length, dimorphic; stamens included; filaments glabrous. Achenes light brown, not winged, 3-gonous, glabrous except for pilose beak. Seeds: embryo curved.
The infrageneric relationships of subg. Clastomyelon are obscure. Preliminary molecular evidence suggests that it is allied to subg. Eucycla.