Monographs Details: Astragalus nuttallianus var. cedrosensis M.E.Jones
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(2): 597-1188.
Family:Fabaceae
Discussion:

333h. Astragalus Nuttallianus var. cedrosensis

Habit of var. imperfectus, the stems usually very slender or filiform, the herbage strigulose, the leaflets thinly pubescent above; leaves mostly 1.5-4.5 cm. long, with (5) 7-11 leaflets, those of the lower leaves cuneate-retuse or -emarginate, or obcordate, 1-5 mm. long, those of the upper leaves linear-elliptic, acute, and up to twice longer; peduncles almost capillary, (0.8) 1.5—8.5 cm. long; racemes 1—3-flow- ered, the axis 0-2 cm. long; calyx about (1.7) 2.5-3 mm. long, the tube (1) 1.4 1.7 mm. long and about as broad, the teeth (0.7) 1-1.6 mm. long; petals whitish or faintly lilac-tinged; banner 3.7—6 mm. long; keel 3.7—4.5 mm., the claws 1.3-2 mm., the lunately triangular blades 2.5-3 mm. long, its apex subacute; pod as in var. imperfectus, (0.7) 1-2 cm. long, 1.6-2 mm. in diameter, the valves minutely strigulose, the septum complete or incomplete.—Collections: 15 (i); representative: Wiggins 5243 (CAS, NY), 6261 (NY, POM); Raven, Mathias & Turner 12,372, 12,562 (CAS); Ripley & Barneby 10,008 (RSA); Brandegee 536 (DS, NY).

Desert flats, stony hillsides, and boulder-strewn washes, mostly below 900 feet, commonly with Larrea, apparently not very common, Baja California, near the Pacific Coast between 25° 40' and 30° N. and on the Gulf Coast from 29° N. to the lower western edge of the Colorado Desert in San Diego and Imperial Counties, California; also in westcentral Sonora, apparently up to 2300 feet, along the upper Magdalena River.—Map No. 150.—December to April.

Astragalus Nuttallianus var. cedrosensis (of Cedros Island) Jones, Rev. Astrag. 270, Pl. 68. 1923.—"Cedros Island, Lower California, Palmer, No. 692."—Holotypus, collected March 18-20, 1889, US! isotypi, GH, ND, NY!—A. cedrosensis Vasey & Rose in Contrib. U.S. Nat. Herb. 1: 15. 1893, nomen.

Astragalus pertenuis (thin) Greene, Leafl. Bot. Obs. 2: 42. 1910.—"A Lower California species, known to me in flowering specimens from Los Angeles Bay and in fruiting ones from Cedros Island, all collected years ago by Edward Palmer."—Holotypus (Palmer 571 from Los Angeles Bay), collected in November or December, 1887, ND! isotypus, NY! paratypi (Palmer 692, from Cedros Island) cited above.—Hamosa pertenuis (Greene) Rydb. in Bull. Torr. Club 54: 329. 1927.

The var. cedrosensis resembles the most slender phases of either var. austrinus or var. imperfectus in habit of growth and outline of the pod, and is recognized principally by its dimorphic leaflets. The extreme form has almost threadlike stems and peduncles, small and distant leaflets, and minute, whitish flowers. The shallow calyx-tube recalls that of var. austrinus, but the short, comparatively short-hairy teeth and the often imperfectly septate or subunilocular pod are more nearly like those of var. imperfectus. Ambiguous specimens from Sonora and from the head of Coachella Valley in California bear witness to morphological confluence of the three varieties. I have not seen Parish 9656 from the Mohave Desert, cited as Hamosa pertenuis by Rydberg (1927, l.c.), which may furnish another example of a few retuse leaflets in var. imperfectus, a minor variation mentioned under the preceding.