Astragalus beckwithii var. purpureus M.E.Jones

  • Authors

    Rupert C. Barneby

  • Authority

    Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(2): 597-1188.

  • Family

    Fabaceae

  • Scientific Name

    Astragalus beckwithii var. purpureus M.E.Jones

  • Type

    "... never has been found east of the Deep Creek Mountains in the western edge of Utah."— Lectotypus, collected at Aurum, White Pine County, Nevada, Jones in 1893, POM!

  • Synonyms

    Astragalus artemisiarum M.E.Jones, Phaca artemisiarum (M.E.Jones) Rydb., Phacomene artemisiarum (M.E.Jones) Rydb.

  • Description

    Variety Description - Wholly like var. Beckwithii, slender and often low, the stems (0.2) 1.5-2.5 dm. long; stipules 1.5—6 mm. long; leaflets (11) 13—27, oval, orbicular, or obovate, truncate or retuse, 3—12 mm. long, the herbage pale green or commonly glaucescent; bracts 1.5—3.5 mm., bracteoles 0—1 mm. long; calyx very thinly black-strigulose, 7—9.5 mm. long, the tube 4.7—5.7 mm. long, 3.2—4.4 mm. in diameter, the teeth 2—4.3 mm. long; banner 17-21 mm., keel 11. 5—14 mm. long; pod as in var. Beckwithii but usually more brightly mottled.

    Distribution and Ecology - Gravelly flats, hillsides and gullied knolls, with piñons and sagebrush, almost exclusively calciphile, 5900-7300 (8000) feet, locally abundant in the valleys and foothills of eastcentral, central, and southern Nevada, extending east just across the State line into western Juab and Beaver Counties, Utah.—Map No. 106.—May and June.

  • Discussion

    The flowers of many species of Astragalus vary in color from one population to another, but the color-forms are only rarely segregated geographically as in A. Beckwithii and its vicariant var. purpureus. When Jones raised his variety to the rank of species, he stressed as differential characters not only the purple flower but also a more fleshy pod and more evident joint between the pod and the gynophore. Returning to the subject a few years later (1900, p. 46), he remarked that the pod of A. artemisiarum was more brightly mottled, the whole plant less leafy, and the leaflets smaller. However, none of these differences is consistently found in purple-flowered plants, which can be distinguished ultimately only by the coloring of the petals. Over most of its range the flowers of var. purpureus are of a vivid purple hue, but in western Nevada, especially in northern Nye and Esmeralda Counties, an albino mutant forms uniform colonies, the loss of anthocyanin being expressed also in the faint or obsolete mottling of the pod. White flowers turn yellowish on drying, and specimens of this variant cannot be distinguished in the herbarium from typical var. Beckwithii. In the field, however, the fresh petals (Ripley & Barneby 3739, CAS, RSA) are strikingly different from those of var. Beckwithii, being clear white faintly lavender-tinted at base of the blades, not cream-colored and con- colorous.

    A peculiar form of var. purpureus, with stiffly erect pedicels up to 6-14 mm. long, variously distorted calyces and only a few fertile flowers, has been collected in the White Pine Mountains (Ripley & Barneby 9318). It resembles one plant of an otherwise normal collection of A. oophorus from the Paradise Range in Lander County (Maguire & Holmgren 25,384, WS). Both seem analogous to the so-called "grallator" form of A. bisulcatus, more fully discussed under that heading. Plants of var. purpureus, which were collected at Indian Springs and southward toward Las Vegas in Clark County, have been reported (Lakin & Hermann in Amer. Jour. Bot. 27: 245. 1940) as containing from 35 up to 950 ppm. of selenium. The sampled populations were associated with Stanleya, but A. Beckwithii is not confined to selenium-rich soils and ordinarily lacks the characteristic odor of the selenium-converter. A mistake in identity may possibly have occurred, for A. Preussii, a consistently seleniferous species of Astragalus, is common in Clark County and superficially similar to var. purpureus.

  • Objects

    Specimen - 01244581, I. W. Clokey 7989, Astragalus beckwithii var. purpureus M.E.Jones, Fabaceae (152.0), Magnoliophyta; North America, United States of America, Nevada, Clark Co.

    Specimen - 796466, B. Maguire 25233, Astragalus beckwithii var. purpureus M.E.Jones, Fabaceae (152.0), Magnoliophyta; North America, United States of America, Nevada, Esmeralda Co.

    Specimen - 796486, B. Maguire 25297, Astragalus beckwithii var. purpureus M.E.Jones, Fabaceae (152.0), Magnoliophyta; North America, United States of America, Nevada, Nye Co.

  • Distribution

    Utah United States of America North America| Nevada United States of America North America|