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Astragalus canadensis var. mortonii
Astragalus canadensis L. var. mortonii (Nutt.) S. Watson
Morton's Canadian Milkvetch
Fabaceae (Pea family)
Synonym(s): Astragalus mortonii
USDA Symbol: ASCAM3
USDA Native Status: L48 (N), CAN (N)
"Usually robust, more rarely quite slender caulescent perennials, the stems arising singly and few together from oblique or horizontally spreading, at length woody rhizomes, thinly strigulose, the hairs up to 0.3-0.65 (0.7) mm. long, the leaflets commonly glabrous but sometimes densely pubescent above, the inflorescence (especially the bracts) nearly always pilosulous with some longer, looser, basifixed hairs up to 0.5-1.1 mm. long, the herbage dark green, the thin-textured, often visibly nerved leaflets usually somewhat bicolored, paler beneath than above; stems relatively slender, erect, simple, (2.5) 3-7 (9) dm. long, fistular when stout, green or purplish, leaflets at base, simple or branching upward." (bibref: 1814).
"The A. c. 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." (bibref: 1814).
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Plant Characteristics
Duration: PerennialHabit: Herb
Leaf Arrangement: Alternate
Fruit Type: Legume
Size Notes: "Stems relatively slender, erect, simple, (2.5) 3-7 (9) dm. long." (bibref: 1814).
Leaf: "Stipules deltoid, deltoid-acuminate, or lanceolate, 3.5-11 (14) mm. long, membranous, pallid, early becoming scarious, the sheathing lower ones not ruptured, persistent; the median and upper ones commonly decurrent around about half the stem's circumference, all thinly pubescent dorsally and often beset, especially at the point of insertion, with a few minute knob- or tack-shaped processes; leaves (3) 6-19 (22.5) cm. long, shortly petioled or the upper ones subsessile, with (9) 13-19 (21) ample, thin-textured leaflets 1-4.5 (5) cm. long." (bibref: 1814).
Flower: "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." (bibref: 1814).
Fruit: "Pod erect, sessile on the slightly elevated receptacle, oblong-cylindroid or -ellipsoid, (9) 11-20 mm. long, 3-5 mm. in diameter, rounded or truncate at base, abruptly contracted distally into a rigid, erect or quite strongly porrect, cusplike beak (3) 3.5-5 mm. long, either terete or grooved dorsally, obtusely carinate ventrally by the prominent, thick suture, the green, somewhat fleshy, glabrous, strigulose, or exceptionally villosulous valves becoming stiffly papery or leathery, brown and ultimately blackish, transversely rugulose-reticulate and sometimes also tuberculate and wrinkled lengthwise, filamentous within, inflexed as a complete or subcomplete septum (2) 2.5-3.4 mm. wide; dehiscence tardy, through the beak and part way downward through the ventral suture; ovules (16) 18-26; seeds greenish, ochraceous, grayish-brown, or castaneous, smooth but dull, 1.7-2.4 mm. long." (bibref: 1814).
Bloom Information
Bloom Color: White , Yellow , Green , PurpleBloom Time: Jun , Jul , Aug , Sep
Bloom Notes: "Petals greenish-white or ochroleucous, the banner often margined with lurid purple." (bibref: 1814).
Distribution
USA: ID , MT , OR , WACanada: BC
Native Distribution: "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." (bibref: 1814).
Native Habitat: "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." (bibref: 1814).
Bibliography
Bibref 1814 - Atlas of North American Astragalus Volume 2 (1964) Barneby, Rupert C.Search More Titles in Bibliography
Additional resources
USDA: Find Astragalus canadensis var. mortonii in USDA PlantsFNA: Find Astragalus canadensis var. mortonii in the Flora of North America (if available)
Google: Search Google for Astragalus canadensis var. mortonii
Metadata
Record Modified: 2020-12-07Research By: Joseph A. Marcus