Astragalus Kentrophyta var. elatus

  • Title

    Astragalus Kentrophyta var. elatus

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Astragalus kentrophyta var. elatus S.Watson

  • Description

    94h. Astragalus Kentrophyta var. elatus

    Suffruticulose and often bushy-branched at base, with ± rigid erect, assurgent, or more rarely diffuse and trailing, herbaceous stems (1) 1.5-4.5 dm. long, the intemodes mostly developed and up to 1.5—5 cm. long, some of them usually longer than the stiff, prickly, early recurving leaves, the stems and herbage strigulose with appressed or narrowly ascending hairs up to 0.5—1 mm. long, cinereous or canescent, the stems sometimes more densely pubescent than the leaves and canescently villosulous; stipules (1) 1.5—12 mm. long, the short, scarious lower ones connate into a bidentate sheath, the upper ones lance-acuminate, herbaceous becoming stiffly papery, connate at base only, thence drawn out into spinescent, divaricate or recurved blades; leaves 1-2.6 cm. long, (3) 5-7-foliolate, the linear- elliptic leaflets (2) 5-15 (17) mm. long, either glabrous or pubescent above, the terminal spinule 1-2.5 mm. long; peduncles 1-6 mm. long, nearly always shorter than the stipules; calyx 3.4—4.4 mm. long, the tube 1.8—2.3 mm. long, 1.6—1.9 mm. in diameter, the teeth 1.5—2.4 mm. long; petals whitish, or faintly purple- veined or -tinged; banner 4.8-6.2 mm. long, 3.2—4.1 mm. wide; wings 4.5-5.6 mm. long, the claws 1.3-1.9 mm., the blades 3.6-4.2 mm. long, 1.5-1.9 mm. wide; keel 3.7—4.1 mm. long, the claws 1.3-1.8 mm., the blades 2.3-2.6 mm. long, 1.4-1.6 mm. wide; pod narrowly ovoid-acuminate, (3.5) 4-7 mm. long, 1.5-2 mm. in diameter, oblique or gently incurved, the ventral suture straight, concave, or at least less convex than the dorsal one, the dorsal suture always convex; ovules 2-4.—Collections: 28 (vii); representative: Purpus 6275 (NY); Eastwood & Howell 789, 7178 (CAS); Ripley & Barneby 4777 (CAS, RSA), 10,269 (RSA); Parker & McClintock 6323 (NY).

    Clay knolls, benches, and talus under cliffs or on steep, boulder-strewn hillsides and canyon washes, 5050-7250 feet, rather common in the pinon belt of the Colorado Basin in northern Arizona, southern Utah, and western Colorado, where associated with red or white sandstones, extending into extreme northwestern New Mexico and into the Green River Basin in southwestern Sweetwater County, Wyoming (where sympatric with var. Jessiae); also north and west in Utah through the Sevier Valley, sometimes on limestone or rarely eruptive bedrock, to eastern Nevada; apparently isolated, at 10,000 feet, on limestone, in bristle- cone pine forest, at the south end of the White Mountains and the adjoining Inyo Mountains in Inyo County, California.—Map No. 38.—June to September.

    Astragalus Kentrophyta var. elatus (tall) Wats., Bot. King 77. 1871.—"Holmes Creek Valley, Nevada. (281)."—Holotypus, collected in September, 1868, GH! isotypi, NY, US (fragm.). A. viridis var. impensus (large or strong) Sheld. in Minn. Bot. Stud. 1: 118. 1894, an illegitimate change of epithet. A. viridis var. elatus (Wats.) Ckll. in Bot. Gaz. 26: 437. 1898. A. Kentrophyta var. impensus (Sheld.) Jones, Contrib. West. Bot. 10: 63. 1902. Kentrophyta impensa (Sheld.) Rydb. in Bull. Torr. Club 32: 665. 1905. A. impensus (Sheld.) Woot. & St. in Contrib. U. S. Nat. Herb. 19 (Fl. New Mex.): 369. 1915. A. montanus var. impensus (Sheld.) Jones, Rev. Astrag. 80, Pl. 5. 1923. A. tegetarius var. elatus (Wats.) Barneby in Leafl. West. 6: 100. 1951.

    In the early spring months an average plant of the tall kentrophyta, var. elatus, presents an unpromising tangle of dead stems which mask the new shoots beginning to arise from the suffruticose caudex. In the Colorado Basin the period of active growth starts in late April or May, at a time when the majority of flowering plants are already well advanced, and the stems continue to elongate until late summer, probably for as long as temperature and moisture, derived from deep in the earth, permit. Under favorable conditions racemes are produced at many successive axils upward along the stems, and the flowering season is thus unusually prolonged. At first relatively weak and pliant, the stems early become rigid and wiry, while the stiff, prickly leaves are quickly arched downward and backward toward the stem-axis. The erect or more rarely trailing stems are unusual in the species, because they are simple above the immediate base rather than repeatedly and diffusely branched throughout. The long internodes, lanceolate, ultimately acerose upper stipules, and distally acuminate, few-ovulate pod are characteristic.

    Since my revision of the species in 1951, at which time its range (always excepting the irrelevant element from the Columbia Basin described above as var. Douglasii) was eminently a natural one, the tall kentrophyta has turned up in two stations in the White and Inyo Mountains in California, at points notably remote from the nearest recorded locality on the Muddy River in southeastern Nevada, and at unexpectedly great elevations near the 10,000-foot contour. The specimens (J. & L. Roos 5820, 5962, RSA) are unusual in having relatively short stems (scarcely 1 dm. long at maturity of the early fruits) and the pods, although distinctly broadest near the base, are less oblique in profile and less distinctly beaked than seen hitherto in var. elatus. Possibly they represent a distinct variety.