Astragalus mollissimus var. Matthewsii

Acaulescent or nearly so, the stems not over 1.5 cm. long, concealed by imbricated stipules (3) 4-8 mm. long, the herbage villous with loose hairs up to 1-2 mm. long, silvery-canescent or greenish; leaves (3) 5-12 cm. long, with 11-23 obovate leaflets 3-12 mm. long; peduncles scapiform, (1.5) 2.5-8 cm. long; racemes (5) 7-12-flowered, the axis (0.5) 1-4.5 cm. long in fruit, not or scarcely surpassing the foliage; calyx 10—13 mm. long, the tube 7—8.6 mm. long, 3.4—4.7 mm. in diameter, the teeth 2.4-5.2 mm. long; petals pale purple; banner 18.5-22.5 mm long; wings 16.8—20.3 mm. long, the claws 8.4—10.7 mm., the blades 9.4—11.1 mm. long, 2.7-3.1 mm. wide; keel 14.2-18 mm. long, the claws 8.7-11.5 mm., the blades 6-7.5 mm. long, 3.5-3.9 mm. wide; pod broadly and plumply ovoid, widest near the obtuse or truncate base, 12—18 mm. long, turgid and 7—13 mm. in diameter, gently or rather abruptly incurved distally into the conical, obscurely compressed, fully bilocular beak; ovules 24—31.—Collections: 8 (iii); representative: Eastwood 5652 (CAS); Ripley & Barneby 5258, 8421 (CAS, RSA); Castetter 6028, 6029 (NMEX); Hinckley 4383 (SRSC).

Open slopes and hilltops, mostly in yellow pine forest, but descending along canyons into the juniper-piñon belt, in light sandy or gravelly, sedimentary, granitic, or volcanic soils, 6550-8300 feet, uncommon and scattered in the mountains of northwestern New Mexico (Zuni Mountains, McKinley County; Jemez Mountains, Sandoval County; near Santa Fe, Santa Fe County), apparently intergrading in Sandoval County with var. Thompsonae.—Map No. 99.—April to June.

Astragalus mollissimus var. Matthewsii (Wats.), comb. nov., based on A. Matthewsii (Washington Matthews, 1843-1905, ethnobotanist and archeologist, U. S. Army surgeon stationed at Fort Wingate in 1882) Wats. in Proc. Amer. Acad. 18: 192. 1883.—"At Fort Wingate, New Mexico; collected by Dr. W. Matthews, U. S. A."—Holotypus, (Matthews 11, in 1882), GH! isotypi, NY, P, US!—A. Bigelovii var. Matthewsii (Wats.) Jones, Rev. Astrag. 231, Pl. 58. 1923.

The Matthews woolly locoweed, the last of the four forms of A. mollissimus with pod bilocular up to the apex of the beak, closely resembles both the last, var. mogollonicus, in stature, although easily distinguished by its tumid fruit of plump outline and few-flowered racemes, and the next in order, var. Thompsonae, with which it intergrades on and near the Continental Divide in Sandoval County. Characters ordinarily and ideally distinguishing var. Matthewsii from var. Thompsonae are the dwarfer growth-habit, fewer flowers, and pod with much less pronounced, less incurved, and fully bilocular beak. The calyx-teeth of var. Matthewsii are either longer or at least longer relative to the tube than in var. Thompsonae, but the flowers are otherwise nearly identical. The present variety thus serves as a bridge linking the group of races typified by var. Bigelovii with the relatively distant var. Thompsonae of the Colorado Basin. Some phases of the southern and central Mexican var. irolanus have pods as plumply turgid as those of var. Matthewsii, but the beak is there unilocular, and the 23-33 leaflets larger and more numerous.