Astragalus tephrodes var. tephrodes

Low and often relatively slender, the herbage pilosulous with ascending or incurved hairs up to (0.4) 0.5-0.75 mm. long, the leaflets glabrous or medially glabrescent above; stems 1-12 (15) cm. long; stipules 2-7 mm. long; leaves 4.5-10 (19) cm. long, with (11) 17-27 (31) obovate-cuneate or oblanceolate, obtuse, emarginate, or subacute, nearly always loosely folded leaflets 3-16 mm. long; peduncles 4-14 (17) cm. long; racemes (9) 11-20-flowered, the axis 2-6 (8.5) cm. long in fruit; calyx (5) 6.4—8.5 (9.2) mm. long, the tube (3.5) 4.5—6.8 (8) mm. long, 3.2-3.9 mm. in diameter, the teeth 1.2-2.2 mm. long; banner 11.8-17.5 mm., wings 11.8-17.5 mm., keel 10.2-14.5 mm. long; pod obliquely ovoid-acuminate, 1.3—2 cm. long, 5—8 mm. in diameter, the beak 3—6 mm. long, the valves thinly leathery, hardly rigid, not rugulose, densely pilosulous; ovules 26-31; seeds 1.8-2.2 mm. long.—Collections: 43 (v); representative: Wooton in 1891 (NMC, POM), in 1893 (NY), approximate topotypi; Jones 26,182 (CAS, GH, POM); Barneby 11,175 (CAS, RSA); Rusby 90½ (GH, NY, POM); Eggleston 19,947, 19,952, 19,953, 19,955 (NY).

Open stony hillsides, sandy gullied bluffs, and rolling plains, in oak brush, among junipers, in yucca-grassland, and ascending into the lower edge of the yellow pine forest, on granitic or volcanic bedrock, 4700-7000 feet, locally plentiful about the foothills of the Mogollon and Pinos Altos Mountains in southwestern New Mexico, east to the Organ Mountains on the Rio Grande, south just into northeastern Sonora; apparently isolated within the range of var. brachylobus in the Verde Valley, Arizona. Reports of var. tephrodes from western Texas and from near Albuquerque, New Mexico (Barneby, 1947) were based on flowering collections of A. Waterfallii and A. feensis respectively.—Map. No. 81.— April to June.

Astragalus tephrodes (ash-gray) Gray, PI. Wright. 2: 45. 1853.—"Plains at the base of the Organ Mountains, New Mexico; April."—Holotypus, collected by Charles Wright, April 30, 1852, GH!—Tragacantha tephrodes (Gray) O. Kze., Rev. Gen. 948. 1891. Xylophacos tephrodes (Gray) Rydb. in Bull. Torr. Club 52: 156. 1925. A. tephrodes var. typicus Barneby in Amer. Midi. Nat. 37: 465. 1947.

The center of dispersal of the relatively small-flowered typical variety of the ashen milk- vetch, var. tephrodes, lies on the watershed of the Gila River and the Rio Grande in southwestern New Mexico. It is abundant in northern Grant County, where it has been encountered at intervals during the past century by most of the many botanists active in the region of the Copper Mines, Silver City, and Mimbres; we thus possess an unusually complete herbarium record from its restricted area and presumably a detailed picture of variation in size of the flowers. Having collected var. tephrodes in seasons both of scanty and plentiful rainfall, I am fairly certain that flower-size in this species is affected to some degree by moisture available during the spring months. Thus it seems probable that plants from the upper Verde Valley in Arizona which are to be referred to var. tephrodes on the technical basis of small flower-size (mapped as intermediate to var. brachylobus) are likewise seasonal variants of var. brachylobus, the dominant form in Yavapai County. A plant from Seligman, Eastwood 5935 (CAS), already singled out for special mention (Barneby, 1947, p. 466), points to the same conclusion. Here the flower is small, but the pod is both fleshy and glabrous, of a type known only in var. brachylobus and to be matched exactly only in large-flowered populations from the Verde Valley.