Madroño 56: 106. 2009.
Herbs, perennial, 0.4–0.8(–1) m, sometimes glaucous, with caudex and thick, woody rootstocks, not freely rooting, without rhizomes. Stems mostly single, usually erect, sometimes branched distally, solid (sometimes hollow in older, robust plants), sometimes glaucous, proximally densely bristly-hairy, hairs reflexed, stiff, simple, sometimes also coarse, 2–3-rayed, stellate, 1–1.6(–2.5) mm, pustulate, sparser distally, with minute, stellate hairs in inflorescence. Leaves mostly basal, some cauline; stipules usually early-deciduous, linear-lanceolate, 3–7 × 1 mm; proximal petioles 15–18 cm, 3–4 times as long as blade, distal usually to 1/2 times to as long as blade; blades: basal rounded, usually palmately 7-lobed, shallowly incised, 4–8 × 4–8 cm, lobes 1.5–2 cm wide, margins crenate-dentate, 3–7-toothed, apices obtuse; distal 3–10, palmately 5-lobed, deeply incised, 2–6 × 2–6 cm, lobes narrow, linear, 2–3.5 × 2–4 mm, margins entire or 1–5-toothed, surfaces: abaxial stellate-hairy, hairs 6-rayed, 1.5 mm, adaxial hairy, hairs simple, 1.5 mm, distalmost glabrate adaxially and sometimes simple-hairy. Inflorescences erect, open, calyces not conspicuously overlapping except sometimes in bud, unbranched or branched, (5–)10–12(–23)-flowered, elongate, sometimes 1-sided, 10–40 cm; bracts lanceolate, usually undivided, 3–4 mm, shorter than pedicels and calyx. Pedicels (3–)5–10(–15) mm; involucellar bractlets absent. Flowers usually bisexual, infrequently unisexual and pistillate, plants gynodioecious; calyx (7–)9–10 mm, to 12–14 mm in fruit, densely stellate-puberulent; petals pale pinkish lavender, often pale-veined especially when dry, pistillate 10–20 mm, bisexual 20–25(–31) mm; staminal column 7–8(–10) mm, sparsely puberulent; anthers white; stigmas (6)7(8). Schizocarps 6–8 mm diam.; mericarps (6)7(8), 3–4 mm, minutely glandularpuberulent, glabrescent, margins sometimes sharpedged, roughened, strongly reticulate-veined, sides and back deeply pitted, honeycomblike, median line on back but not furrowed, mucro 1 mm. Seeds 2.5 mm. 2n = 60.
Phenology: Flowering May–Jun(–Aug).
Habitat: Open oak woodlands, wet sites, sometimes on serpentine
Elevation: 100–400(–1600) m
Sidalcea celata has been recognized as a local species endemic to Shasta and Tehama counties (especially near Redding) in the northern inner North Coast Ranges; it was previously included within S. malviflora. Hitchcock’s concept of S. celata as a subspecies was broader and included plants from additional counties that do not match the type very well; most have been re-identified as S. asprella or S. oregana. Sidalcea celata has been confused with S. asprella, S. gigantea, and S. robusta and appears to be variable. Its narrow distribution, preference for serpentine, typical lack of elongated rhizomes, basally retrorsely hirsute stems, presence of basal leaves, and relatively large bisexual flowers and fruits are distinctive.