Strombocarpa strombulifera
Argentine screwbean
(c) Guillermo Debandi, some rights reserved (CC BY), uploaded by Guillermo Debandi · licence
Family: Fabaceae · Type: Shrub · Not Native
Strombocarpa strombulifera (Argentine screwbean) is a non-native California shrub in the Fabaceae family, recognized by non-native status, glaucous leaves, and fused petals.
Argentine screwbean is a naturalized shrub found in the southeastern Colorado Desert, specifically in Bard and Imperial County, at elevations around 50 meters in disturbed places. Flowering in July, this plant produces small pale flowers in compact clusters less than 4 centimeters long. Growing as a spreading, rounded shrub under 3 meters tall with zigzag stems bearing short whitish spines, it develops distinctive tightly coiled fruits 1.5 to 5 centimeters long. Its leaves are glaucous and glabrous, composed of one primary pair of leaflets 1 to 3 centimeters long and 4 to 16 secondary leaflets 2 to 10 millimeters long. The fruits are notably curled, giving this plant its intriguing "screwbean" common name.
Identification and appearance
Key characters: Geographically isolated; distinguished by non-native status, glaucous leaves, and fused petals
Habitat and range
Habitat: Uncommon. Disturbed places
Elevation: +- 50 m.
Outside California: native to Argentina
Bloom period
Strombocarpa strombulifera blooms Jul.
How to tell it apart
vs Prosopis: Prosopis (honey mesquite) pods are straight to gently curved and flattened; Strombocarpa pods are tightly spiraled into a coil, the 'screwbean.'; vs Acacia: Acacia has many pairs of pinnae and often globose yellow flower heads; Strombocarpa has only a single pair of primary leaflets, pale flowers in short spikes, and paired whitish nodal spines.; vs Parkinsonia: Parkinsonia is green-barked with tiny leaflets and long straight pods; Strombocarpa is spiny at the nodes with tightly coiled pods.; vs Vachellia: Vachellia has stipular spines and round flower heads with straight to curved pods; Strombocarpa is defined by its tightly coiled fruit and single pinna pair.; vs Olneya: Desert ironwood is a large tree with lavender flowers and straight beaded pods; Strombocarpa is a shrub with pale flowers and coiled pods.
Frequently asked questions
Is Strombocarpa strombulifera native to California?
No. Strombocarpa strombulifera is not native to California (recorded as not native).
When does Strombocarpa strombulifera bloom?
Strombocarpa strombulifera blooms Jul.
What plant family does Strombocarpa strombulifera belong to?
Strombocarpa strombulifera is in the Fabaceae family, genus Strombocarpa.
What habitat does Strombocarpa strombulifera grow in?
Strombocarpa strombulifera grows in Uncommon. Disturbed places.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
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.