Phaseolus filiformis
Slender-stem bean
(c) Jim Morefield, some rights reserved (CC BY), uploaded by Jim Morefield · licence
Family: Fabaceae · Type: Vine · Native
Conservation status: CNPS 2B.1
Phaseolus filiformis (Slender-stem bean) is a native California vine in the Fabaceae family, recognized by Extremely limited California distribution, desert wash specialist.
Slender-stem bean is a rare (CNPS 2B.1) California native perennial found in the southern desert regions of Coachella Valley, Riverside County in desert washes at elevations around 125 meters. Flowering from October to December, this plant produces pink-purple flowers approximately 1 centimeter long with a distinctive keel coil about 2.5 millimeters in diameter. Growing as a trailing or twining vine with many branches emerging from the base, it develops a slender taproot and cylindric or angled stems. Its leaves feature ovate-triangular leaflets generally 1 to 5 centimeters long, often with slight lobing. The plant produces pendant, slightly curved oblong fruits 2.5 to 3.5 centimeters long containing 4 to 6 wrinkled, net-like seeds.
Identification and appearance
Key characters: Extremely limited California distribution, desert wash specialist
Habitat and range
Habitat: Washes
Elevation: +- 125 m.
California counties: Riverside
Outside California: to western Texas, northern Mexico
Bloom period
Phaseolus filiformis blooms Generally Oct-Dec.
Conservation status
CNPS 2B.1
Frequently asked questions
Is Phaseolus filiformis native to California?
Yes. Phaseolus filiformis is native to California (recorded as native).
When does Phaseolus filiformis bloom?
Phaseolus filiformis blooms Generally Oct-Dec.
Where in California does Phaseolus filiformis grow?
Phaseolus filiformis occurs in Riverside, at elevations of +- 125 m..
What plant family does Phaseolus filiformis belong to?
Phaseolus filiformis is in the Fabaceae family, genus Phaseolus.
Is Phaseolus filiformis rare or endangered?
Phaseolus filiformis carries California Rare Plant Rank 2B.1, state rank S1.
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.