Sidalcea calycosa
Vernal pool checkerbloom, Vernal Pool Checkerbloom
(c) Ken-ichi Ueda, some rights reserved (CC BY), uploaded by Ken-ichi Ueda · licence
Family: Malvaceae · Type: Herb · Native
Sidalcea calycosa (Vernal pool checkerbloom) is a native California herb in the Malvaceae family.
Vernal pool checkerbloom is a California native perennial herb found in low-elevation wetland habitats, particularly vernal pool ecosystems. Flowering from April to June, this plant produces pale purple to white flowers 10 to 25 millimeters long with delicate petals. Growing 30 to 90 centimeters tall with stems that often root near the base and range from glabrous to sparsely hairy, it has a distinctive rhizomatous growth pattern. Its basal leaves are crenate with cauline leaves featuring 5 to 11 deep, linear to oblanceolate lobes, creating a complex leaf structure. The flower's calyx is 4 to 12 millimeters long, often tinged with purple and stellate-puberulent, with narrowly ovate lobes that are abruptly pointed.
Identification and appearance
Key characters: Geographically isolated - no sympatric species
Habitat and range
California counties: Mendocino, Sonoma, Tulare, Fresno, Nevada, Amador, Tuolumne, Sacramento, Butte, Calaveras, El Dorado, Merced, Marin, Tehama, Shasta, Napa, Madera, Mariposa, San Mateo, Placer, Stanislaus
How to tell it apart
vs Malva: Sidalcea has no bract ring below flowers and anthers in two circles; Malva has 3 bracts and scattered anthers.; vs Clarkia: Sidalcea has mallow flowers with fused stamens; Clarkia has 4 separate petals and 8 separate stamens.; vs Geranium: Sidalcea has bowl-shaped flowers with fused stamens; Geranium has 5 separate petals and long beaked fruits.; vs Malacothamnus: Sidalcea is herbaceous in meadows; Malacothamnus is a woody shrub in chaparral.; vs Calochortus: Sidalcea is a dicot with 5-petaled flowers; Calochortus is a monocot with 3-petaled flowers from bulbs.
Frequently asked questions
Is Sidalcea calycosa native to California?
Yes. Sidalcea calycosa is native to California (recorded as native).
Where in California does Sidalcea calycosa grow?
Sidalcea calycosa occurs in Mendocino, Sonoma, Tulare, Fresno, Nevada, Amador, Tuolumne, Sacramento and other counties.
What plant family does Sidalcea calycosa belong to?
Sidalcea calycosa is in the Malvaceae family, genus Sidalcea.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.