in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 695. 1836.
Plants 10–40 cm; self-incompatible. Stems (± reddish distally) simple or branched (branches 1–4+ and ascending, or more numerous and spreading, rigid), hirsutulous-hispidulous, ± villous. Leaves (sometimes basal clusters persisting to flowering) mostly alternate, 2–5 cm, ± hispidulous (margins ± densely ciliate, especially proximally). Heads in ± spiciform arrays (1–3 per node). Peduncular bracts (crowded, closely investing, obscuring heads before flowering) lance-elliptic to linear (± flat distally), 3–10 (–15) mm (hirsutulous, bristly and/or pectinate-fimbriate, deeply grooved proximally), apices (often ± reddish) rounded to truncate, tack-glands (0–) 1 (terminal). Phyllaries (± reddish distally) 5–6 mm, abaxial faces hirsutulous, usually bristly, ± shaggy long-hairy near distal margins, tack-glands 0. Paleae 5–6 mm. Ray-florets 1–4; corollas white to pinkish, tubes ca. 2 mm (papillate), laminae ca. 5 mm (central lobes much narrower than laterals, widest at bases, symmetric, laterals asymmetric, sinuses 1/3–1/2 laminae). Disc-florets 5–15; corollas white to pinkish, 5–6 mm. Ray cypselae ca. 2.5 mm, smooth, densely appressed-hairy. Disc cypselae ca. 2.5 mm, appressed-hairy, especially on angles; pappi of ca. 10 lanceolate-aristate scales ca. 4–6 mm. 2n = 14.
Phenology: Flowering spring–summer.
Habitat: Dry, rocky hills, ridges
Elevation: 300–1100 m
Calycadenia villosa occurs in Monterey and San Luis Obispo counties and is often localized. It is in the Center for Plant Conservation’s National Collection of Endangered Plants.