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scadden flat checkerbloom

Nelson's checker-mallow, Nelson's checkerbloom

Habit Herbs, perennial, 0.3–0.7 m, not glaucous, with slender, elongated rhizomes to 1 cm diam. Herbs, perennial, 0.4–1 m, often glaucous, with thick, woody taproot and lateral rhizomes to 500 mm.
Stems

single or in dense patches, erect, solid, hairy, hairs simple, spreading, bristly.

clustered, erect, base decumbent-ascending, solid or ± hollow in age, usually ± glaucous distally, glabrous or sparsely hirtellous, hairs short, appressed, simple.

Leaves

cauline, evenly arrayed on stem;

stipules asymmetric-ovate and auriculate, 10–20 × 10–20 mm, width exceeding stem diam.;

petioles of proximal leaves 7–10 cm, gradually reduced distally to 2 cm, 1–1 1/2 times blade length proximally to 1/2 blade length distally;

blade ovate to elliptic, unlobed, usually (4–)7–8 × (2.5–)4–5 cm, reduced distally, base cordate, margins crenate-serrate, apex acute to rounded, surfaces glabrous abaxially, sparsely hirsute adaxially.

basal and cauline;

stipules sometimes deciduous, lanceolate to ovate, (4–)7–9(–14) × (1.2–)3–4 mm;

petioles of proximal leaves 18–37 cm, 3–5 times as long as blades, distal 5–20 cm, to 1/2–1 times as long as blades;

blades: basal reniform to rounded, unlobed and marginally deeply crenate or very shallowly palmately 5–7-lobed, 6–20 × 6–20 cm, base cordate, apex rounded;

cauline deeply 5–9-lobed, lobes linear-elliptic to oblong-elliptic, margins usually entire, sometimes toothed, surfaces finely, sparsely hairy, hairs mostly simple.

Inflorescences

erect, capitate, ± dense, calyces overlapping, unbranched, 2–10-flowered, not elongate, not 1-sided, 3–5 cm;

proximalmost bracts involucrelike, similar to stipules in size and shape, narrowed to linear distally, usually divided to base, 10–20 mm, longer than pedicels, equaling or slightly shorter than calyx.

erect, spiciform, proximally open, distally dense, otherwise calyces not conspicuously overlapping except sometimes in bud, branched, 20+-flowered, proximalmost flowers spaced usually to 1 cm apart, not leafy-bracted, elongate, not 1-sided, 10–20 cm;

bracts single, purple, mm, hairy;

anthers white;

stigmas (6 or)7 or 8.

Pedicels

1–2 mm;

involucellar bractlets 3, 8–12 mm, equaling or longer than calyx.

Flowers

bisexual;

calyx 8 mm, sparsely to densely bristly, sometimes also stellate-hairy;

petals pink, usually pale-veined, 15 mm;

staminal column 4–6 mm, hairy;

anthers white;

stigmas 7 or 8.

Seeds

1.9 mm.

1.5 mm.

Schizocarps

4–5 mm diam.;

mericarps 7 or 8, 2 mm, glabrous, smooth, back with medial line, mucro absent.

4–5 mm diam.;

mericarps (6 or)7 or 8, 2 mm, roughened, sparsely glandular-puberulent apically, sides finely reticulate to faintly rugose, sometimes also on back, to nearly smooth, not pitted, mucro 0.5–1 mm.

2n

= 20.

Sidalcea stipularis

Sidalcea nelsoniana

Phenology Flowering Jun–Aug. Flowering (May–)Jun–Jul(–Sep).
Habitat Marshes Open fields, meadows, fencerows, remnant prairies
Elevation 700 m (2300 ft) (40–)100–600(–1300) m ((100–)300–2000(–4300) ft)
Distribution
from FNA
CA
[BONAP county map]
from FNA
OR; WA
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

Sidalcea stipularis is the most distinctive and easily recognized species of Sidalcea; it is also among the rarest. It is listed as endangered in California. The ovate unlobed leaves are found in no other Sidalcea species. The relatively large stipules, bracts, and involucellar bractlets are also unique in Sidalcea, making the inflorescence appear involucrate. Studies by K. Andreasen and B. G. Baldwin (2001, 2003) suggested that it is one of the basal species within Sidalcea, and it has probably been long isolated. Sidalcea stipularis is known from the northern Sierra Nevada foothills in Nevada County.

Sidalcea stipularis is in the Center for Plant Conservation’s National Collection of Endangered Plants.

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

Of conservation concern.

Sidalcea nelsoniana is uncommon and persists generally in degraded habitats. It resembles S. campestris and S. virgata, with similar ranges, but is generally less hairy and has a smaller, usually purplish calyx. It has been listed as endangered in Washington and as threatened in Oregon; the number of populations and individuals has greatly declined as a result of land development. It is found in the Willamette Valley area from Multnomah and Washington to Benton and Linn counties in Oregon, and in Cowlitz and Lewis counties in Washington.

Sidalcea nelsoniana is in the Center for Plant Conservation’s National Collection of Endangered Plants.

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

Source FNA vol. 6, p. 355. FNA vol. 6, p. 346.
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. keckii, 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. 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. neomexicana, S. oregana, S. pedata, S. ranunculacea, S. reptans, S. robusta, S. setosa, S. sparsifolia, S. stipularis, S. virgata
Name authority J. T. Howell & G. H. True: Four Seasons 4(4): 20, fig. 16. (1974) Piper: Proc. Biol. Soc. Wash. 32: 41. (1919)
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