Astragalus insularis

Slender, occasionally dimunitive, diffuse, annual or winter-annual, perhaps sometimes persisting into a second season when the stems become a little indurated at base, strigulose with straight or nearly straight, appressed or subappressed hairs up to 0.4-0.7 mm. long, the herbage green or cinereous, the leaflets either equally pubescent on both sides or medially glabrescent or fully glabrous above; stems in seedling or depauperate plants solitary and erect, more commonly 3-several, radiating from the root-crown and incurved-ascending or prostrate, 0.4—3.5 (5.5) dm. long, simple or when vigorous branching up to the first peduncle, and the branches sometimes again branched or spurred, floriferous upward from near or often from well below the middle; stipules thinly herbaceous becoming papery, (1) 1.5-4 (5) mm. long, triangular, deltoid-, or triangular- acuminate, about semiamplexicaul, the blades erect, squarrose, or deflexed; leaves (2) 3-12 cm. long, slender-petioled but the upper ones shortly so, with (7) 11-19 (21) broadly to narrowly elliptic, narrowly oblong, or lanceolate, acute, obtuse, or emarginate, flat or folded (and then often backwardly arched) leaflets 3—19 mm. long; peduncles slender, incurved-ascending or divaricate, 0.8-7 cm. long, shorter than the leaf, racemes loosely 3—9-flowered, the flowers early horizontal and at length declined, the axis (0.5) 1—4 (6) cm. long in fruit; bracts thinly herbaceous or membranous and purplish, ovate or triangular, 0.6-1.3 mm. long; pedicels at first ascending, early arched outward and then decurved, at anthesis 0.4 1.2 mm., in fruit a little thickened, 0.8—2.2 mm. long; bracteoles 0; calyx 3.2—4.5 mm. long, strigulose with mixed black and white hairs, the subsymmetric disc 0.5-0.8 mm. deep, the campanulate or turbinately campanulate, commonly purplish tube 1.8-2.7 (2.9) mm. long, 1.8-2.3 mm. in diameter, the subulate teeth 1.3—2.2 (3) mm. long, the ventral pair commonly longest, the whole becoming papery, ruptured, marcescent; petals reddish-purple, drying violet, the banner with a pallid, striate lozenge in the fold; banner recurved through ± 50-60°, ovate- cuneate, widely notched, 5.5-7.4 mm. long, 3.9-5.3 mm. wide; wings 5-6.5 mm. long, the claws 1.6-2.2 mm., the obliquely obovate, oblanceolate, or narrowly oblong, obtuse, slightly incurved blades 3.5-4.7 mm. long, 1.1-2.2 mm. wide; keel 4.8—6 mm. long, the claws 1.8—2.4 mm., the obliquely triangular or half-obovate blades 3-3.7 mm. long, 1.6-2.1 mm. wide, abruptly incurved through 80-95° to the obtuse or subacute, deltoid, sometimes obscurely porrect apex; anthers 0.3-0.45 mm. long; pod spreading or declined, sessile on the scarcely elevated receptacle, very obliquely to subsymmetrically ovoid-ellipsoid, exceptionally lance-ellipsoid, or subglobose, bladdery-inflated, strongly or obscurely beaked at apex, (0.9) 1.1-2.4 cm. long, 0.5-1.5 cm. in diameter, the thin, pale green but purple-suffused or -dotted, sparsely strigulose valves becoming papery, straminous, subdiaphanous, somewhat lustrous, delicately cross-reticulate, not inflexed, the funicular flange 0.2—1.5 mm. wide; ovules 7—12 (14); seeds brown or ochraceous, rarely pinkish-brown, pitted and wrinkled, dull, 2.3-3.8 mm. long.

The Cedros milk-vetch, A. insularis, is widely dispersed over the Colorado Desert and peninsular Baja California, where its full range is probably still only to be guessed at; it is evidently in process of evolutionary fragmentation. The segments of the species described below as varieties are all about equally variable in stature, presenting, according to the season or accident of habitat, diminutive and fleeting annual forms as well as comparatively vigorous, freely branching, and leafy individuals which sometimes persist into a second year. They differ from one another in characters of fruit-shape, indumentum, and outline of the leaflets.