Sidalcea calycosa subsp. rhizomata
Point reyes checkerbloom, Point Reyes Checkerbloom
(c) Ken-ichi Ueda, some rights reserved (CC BY), uploaded by Ken-ichi Ueda · licence
Family: Malvaceae · Type: Herb · Native
Conservation status: CNPS 1B.2
Sidalcea calycosa subsp. rhizomata (Point reyes checkerbloom) is a native California herb in the Malvaceae family, recognized by marsh habitat and large bracts.
Point reyes checkerbloom is a rare (CNPS 1B.2) California native perennial found in central and northern California Coast Ranges in Mendocino, Sonoma, and Marin counties, occurring in coastal marshes at elevations below 30 meters. Flowering from May to July, this plant produces soft pink to lavender flowers with petals 20 to 25 millimeters long. Growing as a weak rhizomatous herb with dense flowering stems 25 to 50 centimeters tall, it develops sparse leaves along its underground rhizomes and clusters of leaves on its aerial stems. Its leaves are broad, measuring 2.5 to 10 centimeters wide, with distinctive stipules 12 to 18 millimeters long and silky-hairy bracts that partially conceal the flower calyx. The fruit develops in segments approximately 4.5 millimeters long with subtly net-veined sides.
Identification and appearance
Key characters: 5 sympatric species - distinguished by marsh habitat and large bracts
Habitat and range
Habitat: Marshes
Elevation: < 30 m
California counties: Marin, Mendocino, Sonoma
Bloom period
Sidalcea calycosa subsp. rhizomata blooms May-Jul.
Conservation status
CNPS 1B.2
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 subsp. rhizomata native to California?
Yes. Sidalcea calycosa subsp. rhizomata is native to California (recorded as native).
When does Sidalcea calycosa subsp. rhizomata bloom?
Sidalcea calycosa subsp. rhizomata blooms May-Jul.
Where in California does Sidalcea calycosa subsp. rhizomata grow?
Sidalcea calycosa subsp. rhizomata occurs in Marin, Mendocino, Sonoma, at elevations of < 30 m.
What plant family does Sidalcea calycosa subsp. rhizomata belong to?
Sidalcea calycosa subsp. rhizomata is in the Malvaceae family, genus Sidalcea.
Is Sidalcea calycosa subsp. rhizomata rare or endangered?
Sidalcea calycosa subsp. rhizomata carries California Rare Plant Rank 1B.2, state rank S2.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
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.