Sidalcea hickmanii subsp. pillsburiensis

S. R. Hill

J. Bot. Res. Inst. Texas 2: 786, figs. 2 – 4. 2008.

Common names: Lake Pillsbury checkerbloom
Conservation concernEndemic
Treatment appears in FNA Volume 6. Treatment on page 337. Mentioned on page 335, 338.

Plants greenish, 0.1–0.4 m, with small, erect, branched caudex and taproot. Stems erect, green, stellate-hairy, hairs appressed, moderately dense, uniform, 0.2–0.5 mm. Leaves: stipules wide-lanceolate, 3 × 1.3 mm; petioles of midstem leaves 0.6–2 cm, 1/2 times to as long as or longer than blade; blade broadly flabelliform, usually truncate, sometimes wide-cuneate, unlobed, 0.6–1.5 × 0.7–2.2 cm, margins coarsely crenate, surfaces tufted-stellate-hairy. Inflorescences open, not spiciform, unbranched, to 10 cm, to 10-flowered, proximal flowers solitary, axillary; bracts 2 in proximal flowers, 1 in distal flowers, distinct, oblong, narrow, cupped, 3 × 1.2 mm, narrowest at base, longer than pedicels, much shorter than calyx. Pedicels 2 mm, usually not obscured by bracts; involucellar bractlets 3, oblong, 3 mm, 1/2 as long as calyx. Flowers bisexual; calyx 4–5 mm, to 5.5 mm in fruit, densely stellate-puberulent, hairs 0.1–0.6 mm diam.; petals pale pink, slightly pale-veined, 8–10 mm; staminal column 5 mm, minutely puberulent; anthers white; stigmas (4–)6 or 7. Schizocarps 4–5 mm diam.; mericarps usually (4–)6 or 7, 1.5–2 mm, side walls smooth, back and margins with 2–5 corrugations. Seeds 1–1.5 mm.

Phenology: Flowering (Jun–)Jul–Aug.
Habitat: Chaparral, ephemeral drainages
Elevation: 700–800 m


Subspecies pillsburiensis is known from a single population near Lake Pillsbury, North Coast Ranges, Lake County. It appears to be a dwarf most closely related to subsp. viridis and differing in its lower stature, undivided (non-two-fid) bracts, fewer flowers, and less conspicuous, appressed indument.

Of conservation concern.

Selected References


Lower Taxa