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Astragalus ampullarius
Astragalus ampullarius S. Watson
Gumbo Milkvetch
Fabaceae (Pea family)
Synonym(s):
USDA Symbol: ASAM6
USDA Native Status: L48 (N)
"Low, slender, strigulose with flattened, tapering, scalelike hairs up to 0.35 mm. long, the lower emersed intemodes and petioles commonly canescent, the herbage green, the leaflets either thinly pubescent or glabrous beneath, glabrous and brighter green above, ciliate; stems solitary or few together, arising directly from the root-crown, subterranean for a space of 3.5-14 cm., at emergence stouter, bearing 1-2 short branches or spurs at the first, usually approximate, aerial nodes, thereafter simple, erect or ascending, above ground 2.5—7.5 cm. long." (bibref: 1813).
"The gumbo knolls, to which A. ampullarius is rigidly confined, are a remarkable geological feature of the sandstone butte country of the Colorado Basin. Often brightly colored in tones of purple, violet, or rosy-lavender, sometimes with alternating belts of arsenical green or sulfurous yellow, they appear from a distance barren of vegetation but play host to some of the most interestingly modified and specialized plants of the region, among them several species of Phacelia and Eriogonum. Its crown, bearing the annual points of renewal, is buried at a depth of up to a decimeter, and only a few centimeters of the stems appear above the surface. The leaves, crowded on the stem, are arranged in what I might describe as a loose rosette pressed to the ground; the solitary or sometimes two peduncles rise vertically from near the stem’s apex. The pod of A. ampullarius possesses a delicate beauty because of the length and slenderness of the stipe, which bears aloft the proportionately large and plumply swollen, purple-speckled body" (bibref: 1813).
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Plant Characteristics
Duration: PerennialHabit: Herb
Leaf Arrangement: Alternate
Fruit Type: Legume
Size Notes: "Stems solitary or few together, arising directly from the root-crown, subterranean for a space of 3.5-14 cm." (bibref: 1813).
Leaf: "Stipules membranous, pallid, 2.5-6 mm. long, those at the buried nodes connate into a cylindric sheath, the rest amplexicaul and shortly connate, the first above ground ovate, obtuse, the rest drawn out into deltoid or lanceolate free blades, or some upper ones only semiamplexicaul and free; leaves 3-10 (14) cm. long, the petioles commonly widely divaricate, with (7) 11-15 (19) obovate- or ovate-cuneate, rarely elliptic, obtuse or retuse, flat leaflets 6-15 mm. long." (bibref: 1813).
Flower: "Peduncles 1 or 2, the upper one appearing terminal, strictly erect, (1) 2-8 (11.5) cm. long; racemes loosely 6-20-flowered, the axis 1.2-13 cm. long in fruit; bracts membranous, lanceolate, 1.5-3 mm. long; pedicels at anthesis 1-1.7 mm. long, in fruit thickened, straight, ascending, 1.8-3 mm. long; bracteoles 2; calyx 4.8-7 mm. long, thinly black-strigulose, the oblique disc 0.7-1 mm. deep, the membranous tube 4.2-6 mm. long, 2.5-3.5 mm. in diameter, the subulate dorsal tooth 0.5-1 mm. long, the rest either similar, or shorter and deltoid, the orifice oblique, the whole becoming papery, marcescent unruptured; petals all ochroleucous, or purple with white wing- tips and pale, striate eye in the banner, if purple drying violet; banner elliptic or rhombic-elliptic, 13.5-20 mm. long, 5.6-6.8 mm. wide; wings 10.6-18.3 mm. long, the claws 4.4-7.2 mm., the lance-oblong or oblong-oblanceolate blades 7.4-12.5 mm. long, 2.2-2.5 mm. wide; keel 9-12.2 mm. long, the claws 3.3-7 mm., the lunately half-obovate blades gently incurved through 80-90 degrees to the rounded apex; anthers 0.55-0.65 mm. long." (bibref: 1813).
Fruit: "Pod erect, stipitate, the slender, nearly straight stipe 9-19 mm. long, the body broadly ovoid, oblong-ovoid, or subglobose, strongly inflated, 1.2-2 cm. long, 8-11 mm. in diameter, nearly symmetric but commonly a trifle more convex on the dorsal side, truncate at base, abruptly contracted distally into a short, compressed-conic, cuspidate beak, terete or nearly so, esulcate, the thin, green, purple-dotted, glabrous valves becoming purplish-stramineous, papery, either not inflexed or inflexed near the base as a rudimentary septum up to 0.3 mm. wide, the funicular flange narrow, about 0.5 mm. wide; seeds light brown, smooth but dull, 2-2.2 mm. long." (bibref: 1813).
Bloom Information
Bloom Color: White , Yellow , Purple , VioletBloom Time: Apr , May , Jun
Bloom Notes: "Petals all ochroleucous, or purple with white wing- tips and pale, striate eye in the banner, if purple drying violet." (bibref: 1813).
Distribution
USA: AZ , UTNative Distribution: "Rare and local, known only from three (possibly four) narrowly restricted stations along the south base of the Zion Escarpment (Kanab; south of Orderville; east of Washington) in western Kane and Washington Counties, Utah." (bibref: 1813).
Native Habitat: "Barren gumbo-clay knolls derived from disintegrated white or red sandstones, associated with Eriogonum subreniforme Wats., Phacelia cephalotes Gray, or both, 3200-5400 feet." (bibref: 1813).
Bibliography
Bibref 1813 - Atlas of North American Astragalus (1964) Barneby, Rupert C.Search More Titles in Bibliography
Additional resources
USDA: Find Astragalus ampullarius in USDA PlantsFNA: Find Astragalus ampullarius in the Flora of North America (if available)
Google: Search Google for Astragalus ampullarius
Metadata
Record Modified: 2020-12-07Research By: Joseph A. Marcus