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giant checkerbloom

annual checkerbloom, checker mallow, vernal pool checkerbloom

Habit Herbs, perennial, (0.8–)2(–2.5) m, not glaucous except on stems, usually in colonies, with rhizomes to 40–60 cm × (6–)10 mm, glabrescent with reflexed-appressed bristle hairs 2.5 mm. Herbs, annual, rarely perennial, (0.2–)0.3–0.5(–0.9) m, not glaucous, with taproot or rhizomelike stolons to 35 blade; basal blades usually orbiculate, unlobed or slightly palmately lobed, 1–2(–10) × 2–5(–10) cm, wider than long, margins crenate, shiny; cauline blades rounded, deeply 5–9(–11)-lobed, 1–2 × 2–4 cm, lobes linear-elliptic to oblanceolate-obtuse, margins entire, ciliate, surfaces slightly hirsute.
Stems

single, scattered, erect, usually purple tinted proximally, hollow especially towards base, pithy distally, 10–14 mm diam. just distal to base, often glaucous, proximally densely retrorsely bristly-hairy and stellate-hairy, hairs pustulate, 1.5–2.5 mm, distally sometimes glabrous.

Leaves

mostly cauline, basal usually absent;

stipules deciduous, with pink band on stem at base, narrowly lanceolate, (3.5–)5(–8) × 0.7(–1.5) mm;

petioles of proximal leaves 6–8 cm, those of midstem leaves 10–14 cm, 2 times to as long as blade, apex curved with swollen portion or pulvinus 5–6 × 1.8 mm;

blades of proximalmost cauline leaves rounded, shallowly, palmately 4- or 5-lobed, 0.5–0.7 × 0.5–0.7 cm, lobe margins irregularly, sparsely dentate, apices rounded, mid-cauline blades 5–7-lobed, 6.5–12 × 10–13 cm, wider than long, gradually reduced distally, lobes straplike, divided 3/4 to base, lobes 5.5 × 1.5–1.8 cm, margins coarsely dentate, surfaces sparsely, minutely hispid and stellate-puberulent, distal leaves deeply 5-lobed, otherwise similar in shape, leaves immediately below inflorescence greatly reduced, irregularly 2- or 3-lobed.

Inflorescences

erect, spiciform, open, calyces usually not overlapping, usually branched, branches 14–18 cm, each branch 10–20 flowered, not 1-sided, elongate, 5–20 cm;

bracts 1, usually undivided, narrowly lanceolate, often 2-fid, 2.5 mm, equaling or slightly longer than pedicel, much shorter than calyx.

erect, spicate, dense, calyces sometimes overlapping, unbranched or branched, distal stem sometimes leafless, many-flowered, not 1-sided, 2–10 cm, elongating at maturity;

bracts green or purplish, ovate to wide-elliptic, usually 2-fid, sometimes undivided, 2–6(–12) × 2–5 mm.

Pedicels

2–3(–5) mm;

involucellar bractlets absent.

(2–)4–5 mm;

involucellar bractlets absent.

Flowers

bisexual or unisexual and pistillate, plants gynodioecious;

calyx 5–6 mm, to 8 mm in fruit, uniformly, densely stellate-puberulent, surface obscured;

petals pale pink, pale-veined, pistillate 7–9 mm, bisexual (10–)14–20(–25) mm;

staminal column 6–8 mm, stellate-puberulent;

anthers white to cream or pale yellow;

stigmas (6)7 or 8.

bisexual or infrequently unisexual and pistillate, plants gynodioecious;

calyx often purple tinted or scarious, 4–12 mm, silky strigose-bristly at base and on veins, stellate-puberulent;

petals usually pale purple or pink, rarely white, base pale or white, (9–)10–25 mm, pistillate shortest;

stamens: outer filaments connate to apex, tube funnel-like, with continuous rim to which unstalked anthers attach;

staminal column 4–9 mm, hairy in proximal 1/2;

anthers white to pale purple;

stigmas 5–9.

Seeds

1.5 mm.

2–3.5 mm.

Schizocarps

6–7 mm diam.;

mericarps (6)7 or 8, sides 3 mm, thick, back and margins thick, rounded, reticulate-veined, pitted, back with prominent groove, top sparsely glandular-stellate-puberulent, mucro 1 mm.

5–9 mm diam.;

mericarps 5–9, often purple tinted, 2.5–4.5 mm, glabrous, not especially roughened, sides reticulate-veined, back deeply longitudinally grooved, mucro often appressed, 0.5 mm.

Sidalcea gigantea

Sidalcea calycosa

Phenology Flowering Jul–Sep.
Habitat Moist to wet, forested slopes, seeps, stream margins, meadows, coniferous forests
Elevation (600–)900–1700 m ((2000–)3000–5600 ft)
Distribution
from FNA
CA
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

Sidalcea gigantea is likely the tallest Sidalcea species; it can be distinguished also by its range (high Cascades and the northern high Sierra Nevada), retrorse hirsute stem bases, thick, hollow stems, and massive, hirsute rhizome systems. Most large patches appear to be clonal and generally produce either bisexual or unisexual, pistillate stems. Sidalcea gigantea is closely related to, and has been confused with, both S. asprella and S. celata. Its leaves are most like those of S. asprella in that they are usually similar in shape throughout the stem; the tall stems and massive rhizome systems distinguish it from S. asprella, as do its occurrence at higher elevations and its later flowering time.

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

Sidalcea calycosa is variable and found locally in marshes and vernal pools in northern California. The annual, short-taprooted, subsp. calycosa varies in height and branching and is consistent in other vegetative and reproductive features. The perennial subsp. rhizomata has elongated, amphibious stolons somewhat like those of the fern Marsilea and is found in marshes near the coast. It and subsp. calycosa have the same fragile nature and similar morphology, and their distinctive fruits are essentially indistinguishable, having the only multifurrowed or striate surfaces in Sidalcea. Because S. calycosa is not at all fibrous and tough like the other perennials, it is keyed with the annuals.

Subspecies 2 (2 in the flora).

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

Key
1. Plants annual, with taproot, stem base rarely decumbent, rooting; bracts 2–6 mm, not obscuring calyx, glabrous or ciliate; calyces 4–7 mm; petals (9–)10–25 mm; relatively widespread in n, c California.
subsp. calycosa
1. Plants perennial, with rhizomelike stolons rooting at nodes; bracts 8–12 mm, mostly obscuring calyx, silky-hairy; calyces 6–12 mm; petals 20–25 mm; restricted to n, c coastal California.
subsp. rhizomata
Source FNA vol. 6, p. 332. FNA vol. 6, p. 326.
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. 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. stipularis, S. virgata
S. asprella, 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. stipularis, S. virgata
Subordinate taxa
S. calycosa subsp. calycosa, S. calycosa subsp. rhizomata
Name authority G. L. Clifton: Madroño 56: 285, figs. 1 – 3. (2010) M. E. Jones: Amer. Naturalist 17: 875. (1883)
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