Psorothamnus arborescens var. arborescens
Mojave indigo bush
no rights reserved, uploaded by Irene · CC0
Family: Fabaceae · Type: Shrub · Native
Conservation status: CNPS 4.3
Psorothamnus arborescens var. arborescens (Mojave indigo bush) is a native California shrub in the Fabaceae family, recognized by no sympatric species.
Mojave indigo bush is a California native shrub found in southwestern Mojave Desert regions of Kern and San Bernardino counties in desert habitats at elevations of 400 to 800 meters. Flowering from April to May, this plant produces lavender to purple flowers in small clusters. Growing as a dense, spreading shrub 1 to 3 meters tall with grayish-green branches, it develops a distinctive woody structure with multiple stems. Its leaves feature small lanceolate to ovate leaflets, typically 2.5 millimeters or more wide, with a terminal leaflet often aligned with the stem axis. The plant's calyx is 7 to 9 millimeters long and covered in sparse to dense hairs, giving it a distinctive textural appearance.
Identification and appearance
Key characters: Geographically isolated; no sympatric species
Habitat and range
Habitat: Desert
Elevation: 400-800 m
California counties: San Bernardino, Inyo, Riverside, Mono, Kern
Outside California: Mexico
Bloom period
Psorothamnus arborescens var. arborescens blooms Apr-May.
Conservation status
CNPS 4.3
How to tell it apart
vs Psorodendron: Psorothamnus has gland-dotted surfaces and indigo-purple flowers; Psorodendron has smooth surfaces and yellow flowers.; vs Astragalus: Psorothamnus has gland-dotted surfaces and single-seeded pods; Astragalus has smooth surfaces and multi-seeded inflated pods.; vs Dalea: Psorothamnus has petals arising from flower base; Dalea has petals arising from a fused stamen column.; vs Condea: Psorothamnus has pea-shaped flowers; Condea has two-lipped tubular flowers (mint family).; vs Scutellaria: Psorothamnus has pea-shaped flowers; Scutellaria has hooded two-lipped flowers (mint family).
Frequently asked questions
Is Psorothamnus arborescens var. arborescens native to California?
Yes. Psorothamnus arborescens var. arborescens is native to California (recorded as native).
When does Psorothamnus arborescens var. arborescens bloom?
Psorothamnus arborescens var. arborescens blooms Apr-May.
Where in California does Psorothamnus arborescens var. arborescens grow?
Psorothamnus arborescens var. arborescens occurs in San Bernardino, Inyo, Riverside, Mono, Kern, at elevations of 400-800 m.
What plant family does Psorothamnus arborescens var. arborescens belong to?
Psorothamnus arborescens var. arborescens is in the Fabaceae family, genus Psorothamnus.
Is Psorothamnus arborescens var. arborescens rare or endangered?
Psorothamnus arborescens var. arborescens carries California Rare Plant Rank 4.3, state rank S4.
Related species
Other California species in the same genus, family, or bioregion.
- Psorothamnus arborescens var. californicus — California indigo bush
- Psorothamnus arborescens var. minutifolius — Johnson's indigobush
- Psorothamnus emoryi — Dyebush
- Psorothamnus fremontii — Fremont's dalea
- Psorothamnus fremontii var. attenuatus — Narrow-leaved psorothamnus
- Psorothamnus fremontii var. fremontii — Fremont's dalea
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.