Astragalus humistratus var. Hosackiae

  • Title

    Astragalus humistratus var. Hosackiae

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Astragalus humistratus var. hosackiae (Greene) M.E.Jones

  • Description

    100d. Astragalus humistratus var. Hosackiae

    Thinly strigulose with relatively short, appressed hairs, or pilose-pilosulous wholly or in part with longer, narrowly ascending ones, the longest up to 0.6-1.2 mm. long, the herbage dark green or greenish-cinereous; stems (4) 7—36 cm. long; stipules (1.5) 2.5-8 mm. long; leaves (1) 1.5-5 cm. long, with 9-15 leaflets 3—10 (12) mm. long; peduncles 2—6 cm. long; racemes 8—20-flowered, the axis (0.8) 1.2-3.5 cm. long in fruit; calyx (3.8) 4-5.5 mm. long, the disc 0.6-0.9 mm. deep, the tube 2.5-3.2 mm. long, 2-2.8 mm. in diameter, the teeth (1) 1.4-2.5 mm. long; petals greenish-white or distally suffused with dull purple,  rarely all violet- or magenta-purple except the whitish wing-tips; banner 6.4-8 mm. long, 5-7 mm. wide; wings 6-7.4 mm. long, the claws 2.1-2.9 mm., the blades 3.8-5.4 mm. long, 1.9-2.5 mm. wide; keel 5.3-6.5 mm. long, the claws 2.2-3.1 mm., the blades 3.2-4.3 mm. long, 1.8-2.2 mm. wide, the apex triangular, not beaklike; anthers 0.4-0.55 mm. long; pod plumply half-ovoid or obliquely ovoid, 7-10 mm. long, (3.6) 4-5.5 mm. in diameter, a little less than 2-2½ times longer than broad, scarcely compressed except in the laterally flattened, cuneiform and cuspidate beak, the ventral suture straight or a little arched either way, the dorsal one strongly convex, not sulcate or at the base only, the valves finely strigulose; ovules (7) 8-14.—Collections: 22 (iii); representative: Kearney & Peebles 13,979 (NY); Eastwood 5911 (CAS), 17,212 (CAS, NY); A. Nelson 1995 (RM, WS); Barneby 12,651 (CAS, RSA); Goodman & Hitchcock 1285 (CAS).

    Dry banks and open flats in yellow pine forest, descending into openings of mixed pine-oak forest or oak-chaparral, chiefly on volcanic bedrock, locally plentiful along and near the crest of the Mogollon Escarpment in southern Coconino, southern Navajo, Gila, and Graham Counties, Arizona.—Map No. 41B.—May to September, either in spring or after summer rain.

    Astragalus humistratus var. Hosackiae (Greene) Jones, Contrib. West. Bot. 10: 58. 1902, based on A. Hosackiae (resembling some species of Hosackia or Lotus) Greene in Bull. Calif. Acad. Sci. 1: 157. 1885.—"Northern Arizona, 1883, Dr. Rusby."—Holotypus, collected near Flagstaff, Coconino County, CAS! isotypi, ND (dated "1882"), NY, OB, US ("No. 579")\ Batidophaca Hosackiae (Greene) Rydb. in N. Amer. Fl. 24: 316. 1929.

    The var. Hosackiae closely resembles some forms of var. humivagans in everything except the glabrescent foliage. It is much less widely dispersed and less variable, the flowers always being relatively small and the pod always short and plump. In northern Gila County and on the Flagstaff Plateau the two varieties are almost equally common and are found in identical environments, but no intermediate populations have been seen.