Astragalus lentiginosus var. variabilis Barneby
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Authors
Rupert C. Barneby
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Authority
Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(2): 597-1188.
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Family
Fabaceae
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Scientific Name
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Type
"...Victor (now Victorville), San Bernardino Co., California, M. E. Jones in 1903 ... "—Holotypus (2 sheets), POM! isotypus, UC!
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Synonyms
Cystium pardalotum Rydb.
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Description
Variety Description - Perennial of short duration or monocarpic, usually coarse, but in dry sites or seasons capable of fruiting from a single stem less than 1 dm. long, the vesture highly variable in orientation and density, most commonly villosulous, sometimes densely villous-tomentulose, sometimes only thinly strigulose, the hairs spreading, ascending, or subappressed, and either straight (or largely so) or sinuous to curly, the longest up to 0.5-0.95 mm. long, the stems nearly always cinereous or canescent, the herbage most often cinereous, sometimes green or silky-canescent, the leaflets pubescent on both sides, sometimes more densely so above than beneath, or nearly to quite glabrous above; stems (0.4) 1-4 dm. long, solitary and erect in seedlings, more often several, diffuse and ascending; leaves (2.5) 4-13 cm. long, with 11-21 (25, or in some young plants only 7-13) obovate-cuneate to broadly oblanceolate or rhombic-elliptic, mostly obtuse or emarginate, more rarely acute or subacute, flat or loosely folded leaflets 4-15 (17) mm. long; peduncles erect or incurved, 3-8 (9) cm. long, shorter than or rarely equaling the leaf; racemes loosely (10) 12-25 (30)-flowered, the axis (3) 4-15 (17) cm. long in fruit; calyx 4.7-6.5 mm. long, thinly and loosely strigulose to densely villosulous with white and often some black or fuscous hairs, the tube 3.7-5.2 mm. long, 2.3-3 mm. in diameter, the teeth 1-1.4 (1.5) mm. long, the ventral pair usually shortest; petals pink- or magenta-purple, exceptionally white; banner 11.1-15 mm. long, 5.5—8 (8.6) mm. wide; wings 9.8—12.8 mm. long, the claws 4.1—5.7 mm., the blades 5.5—8 mm. long, 1.9—3 mm. wide; keel (mostly 0.2—2 mm. shorter, rarely up to 0.2 mm. longer than the wings) 8.4—12.3 mm. long, the claws 4.3-5.9 mm., the blades 4.7-6.7 mm. long, (2.3) 2.6-3.4 mm. wide; pod (1.2) 1.5-2.7 (3) cm. long, the obliquely ovoid or subglobose, bladdery-inflated body 8-14 (15) mm. in diameter, the gently incurved, triangular-acuminate, unilocular beak (3) 4-9 mm. long, the pale green or mottled, finally stramineous and rather firmly papery valves varying from thinly strigulose to densely and canescently strigose- villosulous, the complete septum 3—7 mm., the funicular flange 0.4—1 mm. wide; ovules 23-29.
Distribution and Ecology - Sandy flats, washes, desert playas, sometimes on dunes, commonly with Larrea between 800 and 3000 feet but extending in Kern County west into the southern Sierra foothills up to 5200 feet, common and locally abundant over the southern and southwestern Mohave Desert, California, characteristically developed in eastern Kern, northeastern Los Angeles, and adjoining San Bernardino Counties, passing northward into var. Fremontii in southern Inyo County, and in the central Mohave Desert at low elevations into var. coachellae; also at ± 450-650 feet on the floor of the upper San Joaquin Valley in Kern County, there found mostly along roadsides and in disturbed places, sometimes in natural arid grassland, possibly introduced from the desert, but closely resembling the native var. nigricalycis except for the purple flowers.—Map No. 132.—March to June.
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Discussion
The limits of var. variabilis are drawn to include all the heterogeneous populations of A. lentiginosus (other than the very distinct halophytic var. albifolius) known to occur over the floor of that part of the Mohave Desert lying between the transverse ranges to the southward, the Inyo County line at the north, and the Sierra foothills and the sink of the Mohave River to the west and east. The populations differ greatly one from another in density, distribution, and even type of indumentum clothing the stems and leaves, and together form a body of material, important by reason of individual numbers, which is geographically and morphologically intermediate between var. Fremontii, var. coachellae, and var. nigricalycis. As might be expected in the context of the species, var. variabilis intergrades with each of these vicariant forms. Ideally and abundantly developed on the plains north of the San Bernardino Mountains, the variety is there easily distinguished from var. Fremontii by its larger flower (or at least longer keel), from var. nigricalycis by its purple petals and finer, more appressed and straighter pubescence, and from var. coachellae by its greener leaves, more thinly pubescent pod, and shorter calyx-teeth. A quantity of material has already been cited (Barneby, 1945, p. 124) under the tide of formae (equivalent to the minor variants of this account) to document the passage of var. variabilis into its three neighbors. The first of these, intergradient to var. coachellae, has silvery herbage and canescent pod and is found locally, usually on dunes, in the central Mohave Desert (Ludlow, Baker, etc.). The second, with similarly canescent foliage but pod only thinly and sometimes loosely strigulose, is common along the foot of the Sierra between Owens Lake and Walker Pass, and by gradual shortening of the flower passes directly into the silvery phase of var. Fremontii known as A. eremicus Sheld. The third variant consists of plants in which the purple flowers proper to var. variabilis are combined with the diffuse stems and loose, coarse vesture of the cismontane, yellow-flowered var. nigricalycis. The last is certainly native at the edge of the desert in Kern County and is perhaps a recent immigrant on the Bakersfield Plain. The so-called "carinate" phase of var. variabilis, in which the keel becomes large and prominent, equaling or slightly exserted from between the wings, is locally plentiful about Victorville, Barstow, and Hesperia, in some places occurring in pure stands but in others mixed with the normally graduated type.
The history of the variety has been told elsewhere (Barneby, 1945, l.c.). It was first collected in 1844, by Fremont, on the Mohave River.
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Objects
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Distribution
California United States of America North America|