Sidalcea hickmanii subsp. napensis
Napa checkerbloom, Napa Checkerbloom
(c) Alexander Wentworth, some rights reserved (CC BY), uploaded by Alexander Wentworth · licence
Family: Malvaceae · Type: Perennial · Native
Conservation status: CNPS 1B.1
Sidalcea hickmanii subsp. napensis (Napa checkerbloom) is a native California perennial in the Malvaceae family, recognized by small size and specific habitat.
Napa checkerbloom is a rare (CNPS 1B.1) California native perennial found in the northern Coast Ranges in Napa County, specifically in chamise chaparral with rocky rhyolitic volcanic soil at elevations of 450 to 500 meters. Flowering in May, this plant produces pale pink flowers approximately 9 to 11 millimeters long with delicate overlapping petals. Growing to about 3 decimeters tall with few to several stems that are maroon-tinged and covered in stellate hairs, the plant develops an elongate caudex. Its mid-stem leaves are distinctively 3 to 5-lobed, with the middle lobe being the largest and having toothed tips, and measuring 14 to 18 millimeters long and 20 to 25 millimeters wide. The plant's flower calyces are 7 to 10 millimeters long with acuminate lobes, creating an intricate botanical profile.
Identification and appearance
Key characters: 9 sympatric species - distinguished by small size and specific habitat
Habitat and range
Habitat: Chamise chaparral, rocky rhyolitic volcanic soil
Elevation: 450-500 m
Bloom period
Sidalcea hickmanii subsp. napensis blooms May.
Conservation status
CNPS 1B.1
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 hickmanii subsp. napensis native to California?
Yes. Sidalcea hickmanii subsp. napensis is native to California (recorded as native).
When does Sidalcea hickmanii subsp. napensis bloom?
Sidalcea hickmanii subsp. napensis blooms May.
What plant family does Sidalcea hickmanii subsp. napensis belong to?
Sidalcea hickmanii subsp. napensis is in the Malvaceae family, genus Sidalcea.
Is Sidalcea hickmanii subsp. napensis rare or endangered?
Sidalcea hickmanii subsp. napensis carries California Rare Plant Rank 1B.1, state rank S1.
What habitat does Sidalcea hickmanii subsp. napensis grow in?
Sidalcea hickmanii subsp. napensis grows in Chamise chaparral, rocky rhyolitic volcanic soil.
Related species
Other California species in the same genus, family, or bioregion.
- Sidalcea hickmanii subsp. parishii — Parish's checkerbloom
- Sidalcea hickmanii subsp. pillsburiensis — Lake pillsbury checkerbloom
- Sidalcea hickmanii subsp. viridis — Marin checkerbloom
- Sidalcea hirsuta — Hairy checkerbloom
- Sidalcea keckii — Keck's checkerbloom
- Sidalcea malachroides — Maple-leaved checkerbloom
Sources: Jepson eFlora · CalPhotos · CDFW CNDDB
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.