376. Chamaechaenactis Rydberg, Bull. Torrey Bot. Club. 33: 155. 1906.
Fullstem [Greek, chamae-, creeping, low, on the ground, and generic name Chaenactis]
James D. Morefield
Perennials, 2–7(–9) cm (to 10–20+ cm across). Stems mostly subterranean (caudices relatively thick, branched; aerial stems essentially peduncles). Leaves mostly basal; alternate; petiolate; blades (1- or 3-nerved) cordate, elliptic, ovate, or rounded, margins entire or distally ± crenate, revolute to ± plane, faces ± strigose and gland-dotted, adaxial sometimes glabrescent. Heads discoid, borne singly. Involucres ± obconic, 6–15 (10–23 pressed) mm diam. Phyllaries 11–15 in 2 series (± erect, sometimes spreading in senescence, oblong to oblanceolate, ± unequal, herbaceous, abaxially densely villous, obscurely glandular). Receptacles convex, knobby, epaleate. Ray florets 0. Disc florets 10–30+, bisexual, fertile; corollas white to pinkish, tubes shorter than ± cylindric throats, lobes 5, ± deltate (style branches stigmatic in 2 lines, appendages linear-oblong, blunt). Cypselae clavate, ± quadrangular with 8–12 obscure nerves, densely piloso-strigose, eglandular; pappi persistent, of 7–11, (distinct) oblanceolate to narrowly spatulate, erose scales in 2 series (midnerves prominent). x = 16.
Species 1: w North America.
Chamaechaenactis has been considered a close relative of Chaenactis, which has superficially similar heads. Nuclear rDNA evidence (B. G. Baldwin et al. 2002) suggests closer relationship to Bartlettia, Hymenopappus, and other members of Bahiinae sensu Baldwin. Such a placement was also suggested by Rydberg when he segregated Chamaechaenactis from Chaenactis.
SELECTED REFERENCE
Preece, S. J. and B. L. Turner. 1953. A taxonomic study of the genus Chamaechaenactis Rydberg (Compositae). Madroño 12: 97–103.
