Astragalus eastwoodiae M.E.Jones
-
Authors
Rupert C. Barneby
-
Authority
Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(1): 1-596.
-
Family
Fabaceae
-
Scientific Name
-
Type
"Collected by me ... May 6, 1891, at Westwater, Colo. [perhaps across the Utah line in Grand County], and in fruit only by Miss Alice Eastwood, at Cane Spring, Utah, May, 1892."—Holotypus, Jones in 1891, POM! isotypi, NY, RM, and labeled "Green River," bu
-
Synonyms
Astragalus preussii var. sulcatus M.E.Jones
-
Description
Species Description - Low, loosely tufted, relatively slender, with a woody taproot and shortly forking, suffrutriculose caudex, glabrous except for a few scattered, filiform or scalelike, commonly black hairs on the calyx, pedicels, and margins of the bracts, the thick-textured herbage yellowish-green; stems several or numerous, decumbent and incurved-ascending, 2—10 (14) cm. long, simple or bearing short spurs at 1—3 nodes preceding the first peduncle, and also sometimes between peduncle and petiole, the internodes mostly short, some up to 3 cm. long, mostly shorter; stipules submembranous early becoming papery-scarious, 2-6.5 mm. long, broadly ovate, triangular-ovate, or ovate-acuminate, the lowest often broader than the stem, decurrent around half to nearly the whole stem’s circumference; leaves 3—13 cm. long, shortly petioled, with slender but rather stiff rachis and (9) 13-25, usually distant, scattered, narrowly elliptic, lance-elliptic, or oblanceolate, acute or subacute or (especially in some lower leaves) oblong-obovate to obovate, obtuse, flat or loosely folded leaflets (1.5) 2.5-10 mm. long, the terminal one sometimes confluent with the rachis; peduncles 2-10.5 cm. long, ascending at anthesis, divergent or declined in fruit; racemes shortly but losely 3-7-flowered, the flowers horizontally spreading or declined in age, the axis little elongating, 0.5-3.5 (4) cm. long in fruit; bracts submembranous, becoming papery-scarious, ovate or broadly ovate- triangular, 1.5-4.5 mm. long; pedicels at anthesis ascending, 1.5-2 mm. long, in fruit thickened, arched outward, 2-3.5 mm. long; bracteoles 2; calyx 10-12.2 mm. long, the ± oblique disc 1.6-2.1 mm. deep, the broadly cylindric, membranous, reddish tube 8-9.5 mm. long, 3.6-4.1 mm. in diameter, the subulate teeth 1.3-2.7 mm. long, the whole becoming papery, ruptured distally but marcescent around the stipe; petals pink-purple; banner recurved through ± 45°, broadly rhombic- oblanceolate, notched, 18.5-21.4 mm. long, 8-11 mm. wide; wings 16.6-20.4 mm. long, the claws 9.2-10.7 mm., the linear-oblong, -oblanceolate, or -elliptic, obtuse blades 8.3-12 mm. long, 2.3-2.8 mm. wide; keel 15.4-17.7 mm. long, the claws 9.3-10.7 mm., the lunately elliptic or narrowly half-obovate blades 6.9-8.4 mm. long, 2.8-3.4 mm. wide, gently incurved through 80-90° to the rounded apex; anthers 0.8-0.9 mm. long; pod widely divergent or declined, commonly humistrate, stipitate, the straight or slightly incurved stipe 1.5—4.5 mm. long, the inflated body subsymmetrically or somewhat obliquely ovoid or oblong-ellipsoid, 1.4—2.6 cm. long, (7) 8-14.5 mm. in diameter, turbinately or subtruncately contracted at base, abruptly narrowed distally into an erect, triangular-acuminate, laterally compressed beak ± 2.5-5 mm. long, otherwise subterete or a little obcompressed, then shallowly grooved along one or both sutures, the thinly fleshy, pale green or red-tinged, glabrous or minutely scabrid-puberulent valves becoming papery, stramineous, subdiaphanous, finely reticulate, smooth internally, not inflexed, ovules 20-38; seeds brown, smooth but dull, deeply notched at the hilum 1.8-3.3 mm. long.
Distribution and Ecology - Along draws and creek beds in low gravelly clay hills, on gullied badlands, and on clay banks or benches of arid escarpments, 4300-6250 feet, local but forming colonies, valleys of the Grand, Dolores, and San Miguel Rivers in western Colorado from southcentral Garfield to San Miguel County, west around the foothills of the La Sal Mountains in southern Grand and adjoining San Juan County, Utah and apparently disjunctly in the San Rafael Swell, Emery County.-Map No. 72 -April to June, the fruit sometimes persisting over winter on withered stems.
-
Discussion
The Eastwood milk-vetch is very closely related to A. Preussii. Neither the flowers nor the fruits offer differential characters of any substance, and Jones’s first and last estimate of it as a marked variety is perhaps the correct one. Nevertheless, the plants differ so greatly from all known forms of A. Preussii in their short stems and declined or truly pendulous pods that it is hard to think of A. Eastwoodae as anything but a distinct specific type. Just as the broadleaved phase of A. Preussii seems to have given rise in southern Nevada to a mutant var. laxiflorus, so A. Eastwoodae is presumably derived from the narrow-leaved A. Preussii of the Colorado Basin. The forms of var. Preussii sympatric or nearly so with A. Eastwoodae in southeastern Utah, although similar in foliage and flower, are taller and coarser plants, with erect and ascending stems mostly 2—3.5 dm. long and erect pods of thicker and stiffer texture.
-
Objects
-
Distribution
Utah United States of America North America| Colorado United States of America North America|