Astragalus miguelensis

Diffuse, perennial, with a taproot and at length basally indurated stems, densely woolly-tomentulose with extremely fine, curly or contorted, entangled hairs up to 0.6-1 mm. long, the young stems and foliage white-pannose, becoming gray or greenish-gray in age; stems several or numerous, decumbent and ascending, (1.5) 2-3 dm. long, commonly branched at 1-3 (5) nodes preceding the first peduncle, flexuous or zigzag distally; stipules submembranous becoming firmly papery, 2—5.5 mm. long, tomentulose externally, all amplexicaul and connate, the lower ones through half their length into a short, campanulate sheath, the upper ones more shortly and sometimes obscurely so (the sheath often ruptured by expansion of the stem), with deltoid or triangular-acuminate free blades; leaves (2.5) 4—12 cm. long, shortly petioled, mostly arcuate-recurved, with (17) 21—27 oblong-oblanceolate, -obovate, or -ovate, retuse or obtuse, flat or loosely folded leaflets (3) 6-12 (22) mm. long; peduncles rather stout, (3) 5-13 cm. long, about equaling the leaves, the uppermost often shorter; racemes at first rather dense, 10—30- flowered, the flowers ascending, spreading or a trifle declined in age, the axis not greatly elongating, (1) 2—9 cm. long in fruit; bracts submembranous, dorsally tomentulose, triangular, lanceolate, or lance-acuminate, 2—3.5 mm. long; pedicels ascending, straight or slightly arched outward, at anthesis 0.8—1.7 mm., in fruit 2—3 mm. long; bracteoles 0—2, minute when present; calyx 6.6—7.9 mm. long, white-tomentulose like the herbage, the subsymmetric disc 1—1.6 mm. deep, the campanulate tube 4.1—4.8 mm. long, 3.1—3.9 mm. in diameter, the broadly subulate teeth 2.3-3.5 mm. long, the whole becoming papery, marcescent but ruptured; petals whitish or ochroleucous, concolorous, drying yellowish; banner recurved through ± 45° (further only when withering), broadly obovate-cuneate or rhombic-oblanceolate, 12.5—16 mm. long, (6) 6.8—8.2 mm. wide; wings (2 mm. shorter to 1.3 mm. longer than the banner) 11.6—16 mm. long, the claws 4.5—6.7 mm., the narrowly oblong or oblanceolate, obtuse or erose-emarginate, straight blades 7.7-9.8 mm. long, (2.2) 2.5-3.6 mm. wide; keel (9) 9.3-12 mm. long, the claws 4.6—6.5 mm., the half-obovate blades 5—6.2 mm. long, 2.3—3.3 mm. wide, abruptly incurved through 90—95° to the bluntly deltoid apex; anthers 0.55-0.8 mm. long; pod spreading, sessile, obliquely ovoid-acuminate, bladdery- inflated, obtuse at base, contracted distally into a deltoid or triangular-acuminate, laterally flattened beak, 1.6-2.6 cm. long, (0.9) 1.3-2.3 cm. in diameter, the body a little dorsiventrally compressed, shallowly and openly sulcate along the ventral or both sutures, the thin, pale green or purplish, finely tomentulose valves becoming papery, stramineous, subdiaphanous, delicately cross-reticulate, not inflexed or inflexed as a very narrow septum up to 0.9 mm. wide, the funicular flange also narrow, not over 0.6 mm. wide; ovules 27-40; seeds brown, sometimes purple-dotted, smooth but dull, 1.8—3 mm. long.—Collections: 18 (o); representative: Clokey 4988 (NY, WS); Moran 3445 (CAS, NY, UC); J. T. Howell 3799 (CAS); Abrams & Wiggins 268 (CAS); Mum 6606 (POM, NY); Trask 16 (US); Raven 17,259 (CAS).

Rocky slopes, wind-swept bluffs overlooking the ocean, and beaches or sandy talus beneath sea cliffs, mostly below 500 feet, locally plentiful on the Santa Barbara Channel Islands, California (San Miguel, Santa Cruz, Santa Rosa, Anacapa); San Clemente Island.—Map No. 109.—March to July, and intermittently through the year.

Astragalus miguelensis (of San Miguel Island) Greene in Pittonia 1: 33. 1887 ("Miguelensis").—No locality given, but evidently from San Miguel Island.—No material found (perhaps overlooked) at ND; presumed isotypi, collected on San Miguel by E. L. Greene in September, 1886, G, MO (Greene 3358), NY (2 sheets), ORE, PH!—Phaca miguelensis (Greene) Rydb. in N. Amer. Fl. 24: 348. 1929. A. vestitus var. miguelensis (Greene) Jeps., Fl. Calif. 2: 352. 1936.

The Channel Island milk-vetch, A. miguelensis, is the only insular Californian species with bladdery fruits sessile within the early ruptured calyx, the others having their swollen fruits elevated on either a stipe or gynophore. Its soft woolly-tomentulose vesture distinguishes it on the islands from all but A. Nevinii and A. Traskiae, which have free stipules and nodding, stipitate, uninflated and completely bilocular pods. Despite the differences in the stipules, flowering specimens of A. miguelensis do resemble both A. Nevinii and A. Traskiae and have given rise to misleading reports of these species from several islands to which they are not native. Only A. Nevinii is sympatric with A. miguelensis, and that only on San Clemente Island.

The fruit of A. miguelensis is variable in size and also in the width of the recessive fold arising within from the dorsal suture. Although always very narrow and sometimes obsolete (Moran 3445, NY) it is a true septum, and no mere inward elevation of the suture. On San Clemente Island, remote from the main group of Channel Islands, the pod tends to be smaller and also of slightly firmer texture than elsewhere, but the plants seem not to differ otherwise. The reduction of A. miguelensis to varietal rank under A. anemophilus (or A. vestitus Wats., non Bss. & Heldr.) was perhaps justified; there can be no doubt of the close relationship, mentioned under the preceding. However, Jepson’s suggestion that the species is intermediate between A. anemophilus and A. vestitus var. Menziesii (= our A. Nuttallii) has no foundation in fact.

According to T. D. A. Cockerell, the Channel Island milk-vetch is a locoweed and avoided by sheep on San Miguel Island (Cockerell in 1937, K).