Horkelia howellii
Howell's horkelia
(c) Trevor Van Loon, some rights reserved (CC BY), uploaded by Trevor Van Loon · licence
Family: Rosaceae · Type: Perennial · Native
Conservation status: CNPS 4.3
Horkelia howellii (Howell's horkelia) is a native California perennial in the Rosaceae family, recognized by key diagnostic feature is very low pistil number (2-6).
Howell's horkelia is a California native perennial ranked 4.3 by CNPS, found in the western Klamath Ranges in dry, rocky serpentine clay within open chaparral or pine forest at elevations of 60 to 1,200 meters. Flowering from June to August, this plant produces delicate flowers with petals often pink-tinged, 3 to 5 millimeters long. Growing with tufted green stems 15 to 50 centimeters tall, it forms a few-branched caudex with hairs at the base approximately 1 millimeter long. Its compound leaves are 5 to 15 centimeters long, with about 15 leaflets per side that are crowded and generally lobed almost halfway to the base, creating a dense and intricate foliage structure. The plant produces small fruits 2 to 2.7 millimeters long, nestled in hypanthiums 2 to 3 millimeters wide.
Identification and appearance
Key characters: 7 sympatric species; key diagnostic feature is very low pistil number (2-6)
Habitat and range
Habitat: Dry, rocky serpentine clay, open chaparral or pine forest
Elevation: 60-1200 m
California counties: Del Norte
Outside California: southwestern Oregon
Bloom period
Horkelia howellii blooms Jun-Aug.
Conservation status
CNPS 4.3
How to tell it apart
vs Drymocallis: Horkelia has exactly 10 stamens and white-pink flowers; Drymocallis has 20+ stamens and yellow-white flowers.; vs Erodium: Horkelia has pinnate leaves and rose-family flowers; Erodium has lobed/divided leaves and long-beaked fruits.; vs Phacelia: Horkelia has rose-family flowers with separate petals; Phacelia has bell-shaped fused corollas with protruding stamens.; vs Potentilla: Horkelia has exactly 10 stamens and flattened filaments; Potentilla has 20+ stamens and thread-like filaments.; vs Ivesia: Horkelia has flat leaves with 2-15 separated leaflets; Ivesia has cylindrical bottlebrush leaves with overlapping leaflets.
Frequently asked questions
Is Horkelia howellii native to California?
Yes. Horkelia howellii is native to California (recorded as native).
When does Horkelia howellii bloom?
Horkelia howellii blooms Jun-Aug.
Where in California does Horkelia howellii grow?
Horkelia howellii occurs in Del Norte, at elevations of 60-1200 m.
What plant family does Horkelia howellii belong to?
Horkelia howellii is in the Rosaceae family, genus Horkelia.
Is Horkelia howellii rare or endangered?
Horkelia howellii carries California Rare Plant Rank 4.3, state rank S3.
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 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.