Astragalus canadensis var. brevidens

  • Title

    Astragalus canadensis var. brevidens

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Astragalus canadensis var. brevidens (Gand.) Barneby

  • Description

    188b.  Astragalus canadensis var. brevidens

    Usually of lower, comparatively more robust growth than var. Mortoni, the erect or sometimes decumbent and ascending stems (1) 1.5-5.5 dm. long; herbage usually paler green, the leaflets commonly glabrous but sometimes (especially in western and central Nevada) thinly or even cinereously strigulose above, the hairs up to 0.5-0.9 (1) mm. long, the inflorescence either white- or fuscous-pilosulous; stipules (3) 4-14 mm. long, all connate, but the upper ones often shortly so, the sheath ruptured only in some very robust specimens; leaves 5-15 (23) cm. long, with (7) 15-23 (25) nearly always mucronulate leaflets (0.5) 0.7-3 (4) cm. long; peduncles stout, (4) 5-15 (20) cm. long, either longer or shorter than the leaf; racemes (2.5) 4-9.5 (15) cm. long, 2.5-3.5 cm. in diameter at full anthesis; pedicels in fruit 1.2-3.5 (4) mm. long; calyx (6.8) 7.1-10.5 (11) mm. long, the tube (4.6) 5.1-8.5 (9) mm. long, 3.2-5 mm. in diameter, the broadly subulate or deltoid teeth (1) 1.3-2.5 (3) mm. long, the ventral pair nearly always much broader and commonly shorter than the rest; petals ochroleucous, stramineous, or greenish-white, rarely tinged with dull purple; banner (11.7) 12.5-17 (17.5) mm. long, (4.6) 5-8 (8.8) mm. wide; wings (10.4) 11-15 mm., the claws (5) 5.4-7.4 (7.7) mm., the blades (6.3) 6.7-10 mm. long, (1.6) 1.8-3 mm. wide; keel (8.9) 10-13.6 mm., the claws (4.7) 5.1-7 (7.5) mm., the blades (4.4) 5-7.1 mm. long, (2.2) 2.6-3.5 (3.7) mm. wide; body of the pod (9) 10-15 mm. long, 2.9-4 (4.5) mm. in diameter, the beak 1.5-3 mm. long, the septum 1.5-3 mm. wide; ovules (17) 18-25 (28).—Collections: 171 (vii); representative: Sandberg & Leiberg 341 (CAS, NY, WS); C. L. Hitchcock 16,811 (NY, RSA, SMU, WS), 17,513 (ID, NY, RSA, WS); Cusick 341 (CAS, NY, WS); Hitchcock & Muhlick 9595, 10,759 (CAS, NY, WS, WTU), 12,570 (CAS, NY, RSA, WS); Christ 15,509 (ID, NY, RSA); C. L. Porter 2795 (NY, SMU, TEX, WS); L. S. Rose 50,158 (CAS, NY, RSA); A. Heller 12,904 (CAS, NY, WS); Maguire & Holmgren 22,234 (NY, WS, WT), 26,018 (NY, RSA, WS); Ripley & Barneby 4046 (CAS, NY, RSA, WS).

    Moist but often summer-dry bottomlands, ditches, creek banks, lake shores, hillsides about springs and seeps, alkaline meadows, and depressions on rolling plains, rarely in dry (or apparently dry) sandy or gravelly soils of brushy hills or lava flows, (750 northward) 1500-8100 feet, mostly in stiff, often alkaline, alluvial soils of diverse origin, commonly with sagebrush but ascending along water courses into xeric pine forest, widespread, common, and locally abundant, often forming extensive clumps or colonies, nearly throughout the western and northern Great and Columbia Basins, from eastcentral and northeastern California to interior Washington and southern British Columbia, east to the upper Missouri in southwestern Montana, the upper North Platte River in southern Wyoming and northwestern Colorado, northern Utah, and central Nevada; southwestern Utah (Washington County).—Map No. 75.—June to September.

    Astragalus canadensis var. brevidens (Gand.) Barneby in Leafl. West. Bot. 4: 238. 1946, based on A. Mortoni fma. brevidens (short-toothed, of the calyx) Gand. in Bull. Soc. Bot. Fr. 48: xvi. 1902.—"Nelson exs. no. 3842... Wyoming ad Evanston."—Holotypus, not found and not catalogued (1962) at LY; isotypi, A. Nelson 3842, collected July 27, 1897, NY, RM!

    Astragalus spicatus (spicate, of the raceme) Nutt, ex T. & G., Fl. N. Amer. 1: 336. 1838. —"Plains, near streams, in the Rocky Mountains Range."—Holotypus, labeled by Nuttall "Astragalus * spicatus. R. Mts. Columb.," BM! isotypus, NY!—A. pachystachys (with thick spikes) Rydb. in N. Amer. Fl. 24: 448. 1929, a legitimate substitute (non A. spicatus Pall., 1777) but later homonym (non A. pachystachys Bge., 1869).

    Astragalus tristis (sad, from the black-hairy calyx) Nutt, ex T. & G., FI. N. Amer. 1: 336. 1838.—"Rocky Mountains, towards the sources of the Platte... Nuttall:'—Holotypus labeled by Nuttall "Astragalus * tristis. R. Mts.," BM! ’

    Astragalus Mortoni fma. Rydbergii (Per Axel Rydberg, 1860-1931) Gand in Bull Soc Bot. Fr. 48: xvi. 1902.—"Rydberg, Expl. of Mont. exs. no. 4475 ... in Montana, ad Jack Creek Canon, alt. 7000 ped."—Holotypus, not found and not catalogued (1962) at LY- isotypus, Rydberg & Bessey 4475, collected July 19, 1897, NY!

    Astragalus Torreyi (John Torrey, 1796-1873) Rydb. in N. Amer. FI. 24: 448. 1929.— "Type collected near Empire City, Nevada, in 1865, Torrey."—Holotypus, NY!

    Astragalus brevidens (short-toothed, of the calyx) Rydb. in N. Amer. Fl. 24: 450. 1929.— "Type collected 3 miles north of Whitney, Baker County, Oregon, Febr. [actually July] 22, 1921, M. Peck 10360... "—Holotypus, NY!

    The var. brevidens is closely related to var. Mortoni, with which it has often been inadvertently confused or deliberately united as an inconsequential form. No one familiar with the slender woodland var. Mortoni, as it abounds in the forests of the Northwest, will be content to identify it with the typical and extreme phases of var. brevidens, as this occurs in the deserts of the Great Basin; but at the same time it is difficult to express the perceived reality in exact diagnostic terms. The form of the calyx-teeth, emphasized in the varietal key as a differential character, is somewhat variable. Some individual plants cannot be assigned to either variety on this basis alone unless the growth-habit and pod, unfortunately not often available in a late-flowering species, are taken into account. Practical difficulty occurs, however, only where the ranges of the two varieties meet in eastern Washington and adjacent British Columbia. The forms of var. brevidens found on the upper Columbia River and its affluents sometimes approach var. Mortoni in calycine characters, but the short-beaked pod is densely, often canescently villosulous with short, crisped hairs and thus easily distinguished from the glabres- cent, long-beaked pod of var. Mortoni. In the same area var. brevidens is found around potholes on the basalt plains, about seeps and springs in the coulees, and on the shores of alkaline lakes and ponds; whereas var. Mortoni, although it does come out and down to the edge of the sagebrush around Spokane and elsewhere, is almost always associated with timber. Near their common frontier in southern Idaho and southwestern Montana, the varieties are more abruptly separated morphologically.

    The var. brevidens is less variable than might be expected from its wide horizontal and vertical range, or from the weight of synonymy it has acquired through the years. Nuttall early distinguished two species, A. tristis, based on a single, small, flowering specimen, and A. spicatus, described from a larger, more mature plant. Both fall easily within the range of variation known in var. brevidens, the fuscous calyx of A. tristis being a not uncommon feature of the present variety and by no means diagnostic of var. Mortoni, as Rydberg (1929, p. 441, in clave) assumed. The leaflets of var. brevidens are glabrous above in all parts of its range except central and western Nevada, where they vary from very sparsely to quite densely, at times even canescently strigulose on both faces. This trivial modification seems to be consistent in each colony, but the colonies themselves are probably often clones propagating largely through the sucker-like stolons, and colonies so modified do not occupy any considerable area to the exclusion of the more ordinary glabrescent form. The more pubescent A. Torreyi is therefore to be classed as a minor variant. The plant described by Rydberg as A. brevidens was referred to sect. Hypoglottides, but is a typical example of the present variety and not related to A. adsurgens. The stipules of the holotypus, described as free, are clearly connate. The use of the epithet brevidens in independent descriptions of the same entity was a curious coincidence.

    The short-toothed Canada milk-vetch was first collected on September 15, 1804, by Lewis and Clark on their outward journey (No. 46, PH, labeled "the growth of the open praries").