The following Participating Institutions are custodians for this species in the CPC National Collection:
Rancho Santa Ana Botanic Garden
The conservation of Astragalus tricarinatus is fully sponsored.
Linda Prince contributed to this Plant Profile.
Triple-ribbed milk-vetch is named for its unusual three-ribbed fruits. It is a tuffed perennial (or annual) reaching up to 50 cm in height with distinctly bicolored leaflets, the lower surfaces green and the upper surfaces white hairy. Flowers are light yellow and are produced from February to mid April. The legumes are triangular in cross-section like its presumed closest relative, the Morongo milk-vetch, Astragalus bernardinus (Spellenberg 1993; CVAG 2007)
Distribution & Occurrence
Joshua tree woodland and Sonoran desert scrub communities are the most common areas in which triple-ribbed milk-vetch can be found. Plants are restricted to arid, sandy or gravelly (decomposed granite) canyons. Although most populations of triple-ribbed milk-vetch are found at ~450-700 m elevation along washes, the number of individuals per population is almost always very small (less than 10 plants), thus A. Sanders (unpublished) believes larger populations probably occur upslope. This hypothesis was born out by the recent discovery of a large (300 individuals) population in 2004 (White 2004, 2005) at ~1200 m elevation.
|The species is known from 13 occurrences totaling fewer than 500 plants (CDFG 2007), but highly variable from year to year.|
Conservation, Ecology & Research
Surveys of the slopes above the washes where this species is usually found to better describe habitat preferences, and to delimit extent and size of the populations.