Astragalus canadensis var. Mortoni

  • Title

    Astragalus canadensis var. Mortoni

  • Author(s)

    Rupert C. Barneby

  • Scientific Name

    Astragalus canadensis var. mortonii (Nutt.) S.Watson

  • Description

    188a.  Astragalus canadensis var. Mortoni

    Stems relatively slender, erect, simple, (2.5) 3-7 (9) dm. long; herbage dark green, thinly strigulose, the hairs up to 0.3-0.65 (0.7) mm. long, the inflorescence usually fuscous-pilosulous; stipules 3.5-11 (14) mm. long, the sheathing lower ones not ruptured, persistent; leaves (3) 6-19 (22.5) cm. long, with (9) 13-19 (21) ample, thin-textured leaflets 1-4.5 (5) cm. long; peduncles rather slender, 6-22 cm. long; racemes at full anthesis 2.5-12 cm. long, 2.7-3.5 cm. in diameter, sometimes interrupted toward the base; pedicels in fruit 1.4-2 mm. long; calyx (6.5) 7.4-10.5 (11) mm. long, the tube (5) 5.5-6.7 mm. long, strongly oblique or gibbous at base, (3) 3.4-4.9 mm. in diameter, the teeth (1.5) 2-4.4 mm. long; petals greenish-white or ochroleucous, the banner often margined with lurid purple; banner (12.6) 13.2-16.5 mm. long (4.3) 6-8.2 mm. wide; wings (11.3) 11.7-15.3 mm., the claws (5.2) 5.7-7 mm., the blades (7.3) 7.6-10.5 mm. long, 1.7-2.8 mm. wide; keel (10.4) 10.6-13.1 mm. long, the claws (5) 5.4-6.7 mm., the blades (5.5) 5.7-7.3 mm. long, (2.5) 2.7-3.6 mm. wide; body of the pod (9) 11-20 mm. long, 3-5 mm. in diameter, the beak (3) 3.5-5 mm. long, the septum (2) 2.5-3.4 mm. wide; ovules (16) 18-26.—Collections: 99 (iv); representative: Cronquist & Jones 5901, 5967 (CAS, ID, NY, SMU, RSA, WS); Hitchcock & Muhlick 13,676 (NY, RSA), 13,698, 13,859 (NY, RSA, WS); C. L. Hitchcock 17,572 (ID, RSA, WS), 17,892, 18,177 (ID, NY, RSA, WS); MacDougal & Leiberg 475 (CAS, NY, WS); Ripley & Barneby 10,696 (CAS, RSA).

    Open coniferous forest, thickets in the forest zone, sometimes in deep shade but commonly in glades or openings, in moist or cool acid soils rich in humus, widespread and locally abundant about the north and west affluents of the Columbia River between 3000 and 6800 feet but descending along streams to moist depressions and lake shores in the yellow pine belt as low as 1600 feet, southern British Columbia south through eastern Washington to the Blue and Wallowa Mountains in northeastern Oregon, east through central Idaho and northwestern Montana to Glacier Park and Deer Lodge Valley, extending just over the Divide into the upper Missouri drainage.—Map. No. 75.—June to September, the fruit persisting until snow.

    Astragalus canadensis var. Mortoni (Nutt.) Wats., Bot. King 68. 1871, quoad nom., based on A. Mortoni (Samuel George Morton, 1799-1851, physician and paleontologist, early member and officer of the Philadelphia Academy) Nutt, in Jour. Philad. Acad. 7: 19. 1834.— "About the sources and upper branches of the Missouri... [Nathaniel B. Wyeth]."—Holotypus, labeled in Nuttall’s hand "Astragalus *Wyethii. Sources of the Missouri," with Gray’s annotation "published as A. Mortoni," PH! isotypi, BM! and labeled "A. Mortoni Nutt. Herb. Wyeth.," NY (herb. Torr.)!—Tragacantha Mortoni (Nutt.) O. Kze., Rev. Gen. 946. 1891. Phaca Mortoni (Nutt.) Piper in Contrib. U. S. Nat. Herb. 11 (Fl. Wash.): 372. 1906.

    The var. Mortoni is the commonest milk-vetch encountered in the forest belt in the north half of Idaho, northwestern Montana and eastern Washington, and is sometimes abundant over large areas. It is ordinarily a tall, comparatively slender plant, with thin-textured foliage of a dark green color, a more or less fuscous- or black-hairy inflorescence, and flowers varying from greenish-white to cream-color, often suffused with lurid purple. In the past the name has been applied partly or wholly to the next variety in the majority of texts.