Astragalus puniceus var. puniceus

Title

Astragalus puniceus var. puniceus

Authors

Rupert C. Barneby

Scientific Name

Astragalus puniceus Osterh. var. puniceus

Description

47a. Astragalus puniceus var. puniceus

Leaflets (7) 17-27; bracts herbaceous; bracteoles nearly always present; flowers variable in size, the banner commonly about 16—21 mm., more rarely only 13.5 mm. long; pod mostly oblong-ellipsoid, (4.5) 5-8 mm. in diameter—Collections 14 (i); representative: J. Ewan 13,180 (RSA); Eggleston 20,076, 7, & 8 (NY); Ripley & Barneby 7624 (CAS, RSA, UTC). Low bluffs, sandy mesas, fallow fields, and stabilized dunes, 4700-7000 feet, locally plentiful about the sources of the Canadian River in extreme northeastern New Mexico, adjoining Colorado, and on Black Mesa at the western tip of the Oklahoma Panhandle.—Map No. 18.—May to July.

Astragalus puniceus (red, of the petals, a misnomer) Osterh. in Muhlenbergia 1: 140. 1906.—"Collected at Trinidad, Las Animas county, Colorado, June 28, 1898, no. 1737."— Holotypus, RM! isotypi, NY, POM, RM! Xylophacos puniceus (Osterh.) Rydb. in Bull. Torr. Club 40: 48. 1913. Pisophaca punicea (Osterh.) Rydb. in N. Amer. Fl. 24: 328. 1929.

Astragalus gracilentus var. exsertus (exserted, of the petal-claws) Jones, Rev. Astrag. 195, Pl. 44. 1923.—"Trinidad, Colorado, No. 7, Geo. E. Osterhout, 1898."—Holotypus (= isotypus of the preceding), POM!

There can be no question that A. puniceus and A. Hallii are very closely related, and because of the variation encountered in each it is difficult to find characters of a high order which are consistently differential. In practice the Trinidad milk-vetch, var. puniceus, is readily distinguished from var. Hallii by its fleshier, ultimately thicker-walled and more rigid pod, and by its more densely and loosely pubescent foliage. Where they appear (from the map) to approach each other in range, they occupy different life-zones, and A. puniceus comes into flower a month or more earlier.

The Trinidad milk-vetch is a rather coarse astragalus, but a showy one when in full bloom, the petals being bright pink-purple as in many species of Hedysarum, hardly red as suggested by the epithet. Within its small range of dispersal in Colorado and New Mexico, the flowers are uniformly large; but on the slopes and summit of Black Mesa at the western extremity of the Oklahoma Panhandle occurs a local race, similar in all details of fruit and pubescence, but differing in the shorter calyx and petals. This form may deserve varietal rank, but its recognition must await deliberate search for intermediate colonies. For sake of completeness the characters of the typical and Black Mesa forms, as known up to the present, may be contrasted as follows:

a. Calyx 9.3-10 mm. long, the tube 7-8 mm., 4.2—4.6 mm. in diameter; banner 15-21 mm. long; keel 13-14 mm. long, the claws 6.5-8 mm., the blades 7-7.5 mm. long, 3.3-3.8 mm. wide; Colorado and New Mexico

- var. puniceus (typical)

a. Calyx 6-8.1 mm. long, the tube 4.9-6 mm., 3.5-3.9 mm. in diameter; banner 13.4-16.5 mm. long; keel 10.4-11.5 mm. long, the claws 5.8-6.6 mm., the blades 5.4—5.8 mm. long, 2.6—3 mm. wide; w. Oklahoma

var. puniceus (Black Mesa)

Representative of the Black Mesa form are: Waterfall 9077, 10,735 (OKLA); G. W. Stevens 468 (NY); Goodman & Waterfall 4841 (OKLA).