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Keck's checkerbloom

Butte County checkerbloom

Habit Herbs, annual, 0.1–0.4 m, not glaucous, with taproot. Herbs, perennial, (0.5–)0.8–1.2(–1.8) m, glaucous, with caudex and usually well-developed rhizomes to 0.5 mm diam.
Stems

single, erect, sometimes branched distally, solid, short-stellate-puberulent and long, soft bristly-hairy, distally with multicellular trichomes intermixed, hairs erect.

often single, usually scattered, erect, usually unbranched, solid or somewhat hollow in age, proximally densely, finely stellate-hairy, hairs spreading, distally glaucous, glabrous.

Leaves

cauline, 3–5 per stem;

stipules linear-filiform, undivided or rarely few-divided in robust plants, 3–5 × 1 mm;

petiole 2–4.5(–6) cm, usually 1–2 times as long as blade;

blades: proximalmost orbiculate, unlobed, 1–2.5 × 1–2.5 cm, base cordate with narrow sinus, margins crenate, apex rounded;

other proximals rounded, unlobed or shallowly palmately 7–9-lobed, 2.5–4.8(–6) × 2.5–4.8(–6) cm, margins coarsely crenate, sinus wide to narrow, surfaces stellate-hairy;

distals gradually reduced, orbiculate, more deeply 3-lobed, 1.5–2.5 × 1.5–2.5 cm, lobes obovate, apically widened to nearly truncate and narrowed to base, margins entire, apex 2–5-toothed, teeth subequal.

cauline, mostly on abaxially, bristly-hirsute adaxially.

Inflorescences

erect to ascending, usually open, calyces not overlapping except possibly in bud, unbranched or infrequently branched, 5–12-flowered per branch, not especially elongate, usually 1-sided, 5–10 cm, to 5–15 cm in fruit, 1/2 times plant height;

bracts linear-filiform, undivided or rarely few-divided in robust plants, (3–)7–11 mm, longer than pedicels, usually much shorter than calyx, not involucrelike, densely stellate-hairy and pilose-hirsute.

erect, open, calyces not conspicuously overlapping except sometimes in bud, usually unbranched, loosely 10+-flowered, flowers 1+ cm apart, elongate, sometimes 1-sided, 30–40(–45) cm;

bracts inconspicuous, lanceolate to linear, distal unlobed, 2–4 mm, proximal divided ± to base, 4–6 mm, usually equaling or shorter than pedicels.

Pedicels

2–4 mm, to 5–6 mm in fruit;

involucellar bractlets absent.

2–5 mm;

involucellar bractlets absent.

Flowers

bisexual;

calyx 8–10 mm, to 11–14 mm in fruit, lobe base within with conspicuous, purplish spot 1–2 mm wide, hairy, hairs glandular and non-glandular, multicellular as in inflorescence;

petals dark pink, without pale veins, with or without reddish basal spot, 10–22(–26) mm;

filaments connate to apex of tube;

staminal column 3–5 mm, hairy, hairs relatively long, simple;

anthers white;

stigmas 4 or 5.

usually bisexual, sometimes pistillate, plants gynodioecious;

calyx 10–15 mm, uniformly, densely stellate-puberulent;

petals: bisexual pale pink, often drying yellowish, pale-veined or not, base pale pink to white, (15–)20–35 mm, pistillate usually darker purple, base white, 5(–10) mm;

staminal column 6–8 mm, hairy;

anthers white;

stigmas (6 or)7 or 8.

Seeds

1.5–2 mm.

2–2.5 mm.

Schizocarps

5–7 mm diam.;

mericarps 4 or 5, usually tinted pink when fresh, 3–4 mm, usually glabrous, back reticulate-veined, pitted, with prominent midvein, mucro absent but with 1–5 minute bristles in its place.

6–8 mm diam.;

mericarps (6 or)7 or 8, 3–3.5 mm, usually glabrous or very sparsely glandular-puberulent, distinctly narrowly wing-margined dorsally, sides lightly reticulate-veined, pitted, back less so, mucro 0.3–0.5 mm.

2n

= 20.

Sidalcea keckii

Sidalcea robusta

Phenology Flowering Apr–May(–Jun). Flowering Apr–May(–Jun).
Habitat Grassy slopes, tolerant of, not restricted to, serpentine Dry banks in chaparral at ecotone with foothill woodlands, often basaltic soil, with Quercus douglasii
Elevation 70–700 m (200–2300 ft) 100–400(–1300) m (300–1300(–4300) ft)
Distribution
from FNA
CA
[BONAP county map]
from FNA
CA
[BONAP county map]
Discussion

Sidalcea keckii, federally listed as endangered, was once thought to have been extirpated (S. R. Hill 1993); it was rediscovered in 1992. It appears to have occurred historically in at least seven counties; extant populations are thought to be very few. It is found in the southern inner North Coast Ranges in Colusa, Napa, Solano, and Yolo counties, and in the Sierra Nevada foothills in Fresno, Merced, and Tulare counties. It is closely related and similar to S. diploscypha and is often mistaken for that species; differences between the two are discussed under 8. S. diploscypha. Some plants of S. keckii in Colusa, Solano, and Yolo counties have divided bracts like those of S. diploscypha. Sidalcea keckii is vulnerable to agricultural and residential land development.

Of conservation concern.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Of conservation concern.

Sidalcea robusta is one of the taller species of Sidalcea and can be distinguished also by its relatively long inflorescences with widely-spaced, showy flowers, its limited range, and its winged mericarps are notable. Rare and threatened by development, it is known from Butte County in the southern Cascade Range foothills and the northern Sierra Nevada foothills.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 6, p. 339. FNA vol. 6, p. 353.
Parent taxa Malvaceae > subfam. Malvoideae > Sidalcea Malvaceae > subfam. Malvoideae > Sidalcea
Sibling taxa
S. asprella, S. calycosa, S. campestris, S. candida, S. celata, S. covillei, S. cusickii, S. diploscypha, S. elegans, S. gigantea, S. glaucescens, S. hartwegii, S. hendersonii, S. hickmanii, S. hirsuta, S. hirtipes, S. malachroides, S. malviflora, S. multifida, S. nelsoniana, S. neomexicana, S. oregana, S. pedata, S. ranunculacea, S. reptans, S. robusta, S. setosa, S. sparsifolia, S. stipularis, S. virgata
S. asprella, S. calycosa, S. campestris, S. candida, S. celata, S. covillei, S. cusickii, S. diploscypha, S. elegans, S. gigantea, S. glaucescens, S. hartwegii, S. hendersonii, S. hickmanii, S. hirsuta, S. hirtipes, S. keckii, S. malachroides, S. malviflora, S. multifida, S. nelsoniana, S. neomexicana, S. oregana, S. pedata, S. ranunculacea, S. reptans, S. setosa, S. sparsifolia, S. stipularis, S. virgata
Synonyms S. asprella var. robusta
Name authority Wiggins: Contr. Dudley Herb. 3: 56, plate 13, figs. 2 – 6. (1940) A. Heller ex Roush: Ann. Missouri Bot. Gard. 18: 205. (1931)
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