Astragalus lentiginosus var. diphysus

  • Title

    Astragalus lentiginosus var. diphysus

  • Author(s)

    Rupert C. Barneby

  • Scientific Name

    Astragalus lentiginosus var. diphysus (A.Gray) M.E.Jones

  • Description

    289t. Astragalus lentiginosus var. diphysus

    Perennial, usually stout and coarse, the glabrous stems incurved-ascending in low clumps, the herbage yellowish-green or dark green, thinly strigulose or strigulose-villosulous with mostly straight hairs up to 0.4-0.75 mm. long, the leaflets glabrous above or on both sides; stems simple or branched at base, (1) 1.5-3.5 (4) dm. long; leaves 3-10 (14) cm. long, with (11) 15-21 (23) oblong-oblanceolate, obovate, rhombic-obovate, elliptic, or ovate-cuneate, truncate-emarginate, flat or loosely folded leaflets 4-20 mm. long; peduncles erect or incurved, (1.5) 2.5-8.5 cm. long, shorter than or equaling the leaf; racemes shortly, at first rather densely (10) 12-24-flowered, the axis not or little elongating, 1-4 (6) cm. long in fruit; calyx 7-10.4 mm., the cylindric or deeply campanulate tube (5.1) 5.5-8 mm. long, (2.5) 2.7-3.5 (4) mm. in diameter, the teeth 1.5-3.2 mm. long; petals pink-purple, drying violet, ultimately fading brownish; banner (12.6) 14.5-19 mm. long, (5.8) 7-9.8 mm. wide; wings (11.8) 12.5-16.7 mm., the blades (7) 7.6-9.6 mm. long; keel (11) 11.5-14.7 mm., the blades (5.8) 6.2-1.7 mm. long; pod (1) 1.4-2.7 (3) cm. long, (6.5) 8-18 mm. in diameter, greatly or sometimes little inflated, the body plumply ovoid or subglobose, more rarely (transition to var. palans) narrowly lance-ovoid, abruptly contracted (or when narrow tapering) into a more or less incurved, triangular-acuminate, uni- or bilocular beak (3) 4-10 mm. long, sulcate along both sutures, the green, purple- or red-tinged or brightly mottled valves glabrous, becoming stiffly papery or leathery, the septum (2) 2.5-5 mm. wide; ovules 28-35.—Collections: 66 (x); representative: Rusby 570 (GH, NY, UC); Peebles & Smith 13,964 (NY, SAC); MacDougal 144 (F, GH, NY, PH, POM, UC); Peebles 11,996 (CAS, SAC); McVaugh 14,508 (CAS, NY); A. & G. Heller 3541 (ND, NY, OB, GH); Barneby 12,606 (CAS, RSA).

    Sandy plains, mesas, rocky slopes in canyons, sometimes on dunes or along sandy roadsides, in yucca-grassland, piñon or juniper forest, and other xeric associations, without apparent rock preference, but perhaps most abundant on sandstone and volcanic substrata, 4850-7400 feet, widespread and locally abundant across northern Arizona south of the Colorado River, from the head of the Verde River to the upper Little Colorado, east across the Continental Divide to the Rio Grande Valley in northwestern and central New Mexico, extending rarely north into the southwest comer of Colorado (Mesa Verde) and to the Henry Mountains in Garfield County, Utah.—Map No. 131.—March to June, sometimes again in fall.

    Astragalus lentiginosus var. diphysus (Gray) Jones in Proc. Calif. Acad. Sci. II, 5: 673. 1895, based on A. diphysus (double-bladdered, of the swollen, bilocular pod) Gray in Mem. Amer. Acad. II, 4 (Pl. Fendl.): 34. 1849.—" ... around Sante Fe, in red sandy soil; No. 146."—Holotypus, collected by August Fendler in 1847, GH! isotypi, BM, F, GH, K, MO (2 sheets), NY, P!—Tragacantha diphysa (Gray) O. Kze., Rev. Gen. 944. 1891. Cystium diphysum (Gray) Rydb. in Bull. Torr. Club 32: 659. 1905.

    Astragalus diphysus var. albiflorus (white-flowered) Gray, l.c. 1849.—"With the preceding. No. 147."—Lectotypus, Fendler 147, collected "on light sandy soil on the plains about Santa Fe, May 10, 1847," MO! isotypus, GH (but received long after Gray’s death and not annotated by him)!

    Astragalus MacDougali (Daniel Trembly MacDougal, 1865-1958, from 1905 to 1928 director of botanical research for the Carnegie Institution) Sheld. in Minn. Bot. Stud. 1: 169. 1894 ("macdougali").—" ... near the top of Walnut canon, near Flagstaff, Arizona, June, 1891, by D. T. MacDougal... ’’—Holotypus, MINN! isotypus, US!—Note that Rusby 570, cited by Barneby, 1945, p. 115, as type-collection of A. MacDougali, is not so.—A. lentiginosus var. MacDougali (Sheld.) Jones in Proc. Calif. Acad. Sci. II, 5: 673. 1895. Cystium MacDougali (Sheld.) Rydb. in N. Amer. Fl. 24 : 415. 1929.

    The var. diphysus carries the theme already stated by var. araneosus, one of large, purple flowers followed by shortly racemose, glabrous pods, south and east across the plateaus of northern Arizona into the Four Corners country and the Rio Grande Valley in northcentral New Mexico. The poor differential characters of var. araneosus, allopatric northward, have been mentioned above; within its limits of dispersal var. diphysus is the only freckled milk-vetch encountered on the open plains and on the foothills either below 7000 feet or below the limit of yellow pine, and is easily recognized in practice. In Coconino County, Arizona, one must be careful to distinguish var. oropedii, endemic to the North Rim of Grand Canyon, and on the Flagstaff Plateau var. Wilsonii with its narrow pod of linear-ellipsoid outline.

    The pod of var. diphysus is variable in size and degree of inflation, although no more so than that of most other forms of A. lentiginosus. A phase of it, often of depauperate stature, found in greatest abundance on the thin volcanic soils around the San Francisco Peaks, has a small subglobose or plumply ovoid pod about 1-1.5 cm. long, but seems hardly to deserve taxonomic status (= A. MacDougalli Sheld.). As var. diphysus approaches the canyons of the Colorado in northern Arizona, the pod tends to become less and less swollen, finally passing imperceptibly into var. palans (q.v.). Likewise as we pursue it southward along the Rio Grande, we find evidence of an equally gradual passage into var. australis, ideally distinguished by its longer and looser racemes of thinner-walled fruits.

    According to Jones (1923, p. 155 and Index) A. diphysus var. albiflorus is referable to A. Pattersoni, not to var. diphysus. It is true that Fendler might easily have collected A. praelongus var. Ellisiae (= A. Pattersoni sensu Jones, p. p.) at Santa Fe, but the specimens of his No. 147 as represented at GH and MO are certainly var. diphysus, presumably an albino form although the flowers are now brownish and the color not decipherable. The error on Jones’s part probably arose from a specimen of A. praelongus collected in the Moqui Country in northern Arizona by Newberry in 1858 (US), for this was misidentified by Gray as A. diphysus var. albiflorus and is the only sheet on which I have found this name written in his hand. Granted that var. albiflorus is a taxonomic synonym of var. diphysus, strict adherence to the Rules of Nomenclature require that the earlier in the varietal rank takes precedence. Where the law asks an absurdity and runs counter to common sense and the meaning of words, it loses the respect without which it cannot function legitimately. In the belief that the rule will be modified to deal with cases of this sort, I have avoided proposing the legally required transfer.