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Astragalus bolanderi
Astragalus bolanderi A. Gray
Bolander's Milkvetch
Fabaceae (Pea family)
Synonym(s):
USDA Symbol: ASBO2
USDA Native Status: L48 (N)
"Robust or sometimes quite slender, but always stiff and rather sparsely leafy, with a thick, woody taproot and knotty root-crown or loosely forking caudex, villosulous with fine, ascending, incumbent, or curly, exceptionally subappressed and wavy hairs up to 0.4—0.7 (0.8) mm. long, the stems thinly so and usually glabrous toward the base, the herbage either greenish or canescent, the leaflets equally pubescent on both sides or more thinly so above; stems several or numerous, erect, or decumbent with ascending tips, (1) 1.5-4 (4.5) dm. long, slender and leafless at base, becoming stouter and striate upward, stramineous in age, simple or (in vigorous plants) branched or spurred at 1-3 nodes preceding the first peduncle, commonly zigzag distally." (bibref: 1813).
"The Bolander milk-vetch is the only astragalus found along the west slope of the Sierra, at 6500-10,000 feet, between the valleys of the Kern and Yuba Rivers. It is common in its zone of occurrence where Jepson has described it as forming extensive colonies in sandy meadows and openings of Abies concolor forest, often associated with Eriogonum nudum. The pod of A. Bolanderi is a remarkable one, in some respects unique. The slender but stiff stipe is variably oriented, either spreading, ascending or declined, but the body is set upon it obliquely and is furthermore so strongly incurved as to bring the beak to an attitude vertical to the ground or, more often, pointing inward toward the raceme-axis. The body of the pod is decidedly inflated, of rather firmly papery texture, hardly to be described as bladdery. The structure of the funicular flange is quite unusual; and the number of ovules and seeds unexpectedly low in proportion to the size of the fruit. In general appearance the Bolander milk-vetch is rather sparsely leafy, its habit of growth stiff and awkward. The pubescence of the leaves varies in density, but is usually sparse; the gray-villosulous forms collected in Nevada County (e. g., Sonne 13, ND) seem to represent no more than a minor variant." (bibref: 1813).
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Plant Characteristics
Duration: PerennialHabit: Herb
Leaf Arrangement: Alternate
Fruit Type: Legume
Size Notes: "Stems several or numerous, erect, or decumbent with ascending tips, (1) 1.5-4 (4.5) dm. long." (bibref: 1813).
Leaf: "Stipules scarious, pallid (or early becoming so), (1.5) 2-6 mm. long, the lowest united through half to nearly their whole length into a rather loose, obtusely bidentate (fragile and sometimes ultimately ruptured) sheath, the median and upper ones decurrent around at least half the stem's circumference, free or united by a low collar or stipular line, the blades mostly reflexed, all glabrous dorsally, ciliate, the margins beset with a few minute processes; leaves (3) 4-12 (16) cm. long, the lower ones shortly petioled, the upper sessile or nearly so, with rather stiff rachis and (13) 17-25 (27) usually scattered, narrowly oblong-elliptic, oblanceolate, linear-oblong, or rarely oblong-obovate, acute, rarely subobtuse or (exceptionally, in some lower leaves) retuse, folded or less often flat leaflets (3) 5-20 (23) mm. long, all commonly carinate dorsally by the midrib which runs out into a callous mucro." (bibref: 1813).
Flower: "Peduncles stiffly erect or narrowly ascending, (3) 4-8 cm. long, usually shorter than the leaf; racemes shortly and rather closely (5) 8-18-flowered, the axis little elongating, (0.5) 1-3 (5) cm. long in fruit; bracts scarious, ovate or lanceolate, 1.2-3 mm. long; pedicels at anthesis ascending, slender, (0.8) 1-2 (2.7) mm. long, in fruit a little thickened, straight and ascending, straight and divaricate, or commonly arched outward, (1.1) 1.5-2.5 (3.5) mm. long; bracteoles 0-2, minute when present; calyx (6.4) 7-12 (13) mm. long, villosulous (at times thinly so) with mixed black and white, white and fuscous, rarely all white hairs, the subsymmetric disc (0.9) 1.1-1.8 mm. deep, the tube (4.5) 4.8-6.3 (6.8) mm. long, 3-4.3 mm. in diameter, the subulate or lance- subulate teeth (1.8) 2.5-5.3 (6.2) mm. long, all subequal but the ventral pair usually broadest (the dorsal one sometimes shortest), the whole becoming papery, marcescent unruptured; petals whitish, perhaps sometimes faintly lilac-tinged, drying yellowish; banner rhombic-elliptic or -obovate, 13-17.6 mm. long, 5.2-8 mm. wide; wings 12-15.8 mm. long, the claws 5.8-7.8 mm., the narrowly lanceolate or lance-elliptic, obtuse or rarely subemarginate, straight or slightly incurved blades 7.4-9.2 mm. long, 1.9-3 mm. wide, the narrow tips often obscurely erose and twisted; keel (9.8) 10-12.4 mm. long, the claws 5.7-7.7 mm., the half-obovate blades 4.2-5.6 mm. long, (2.4) 2.7-3.2 mm. wide, rather abruptly incurved through 95-100 degrees to the bluntly deltoid apex; anthers 0.45-0.65 (0.7) mm. long." (bibref: 1813).
Fruit: "Pod variably oriented, stipitate, the straight or slightly incurved, filiform but rigid or upwardly thickened stipe (4) 5-12 mm. long, ascending, divaricately spreading, or even a little declined from the raceme- axis, the very obliquely ovoid or ovoid-acuminate, inflated but scarcely bladdery body set at an angle to the stipe and thus so strongly incurved from its insertion as to bring the beak vertically erect or more often directed inward toward the axis, (1) 1.3-2 4 (3 2) cm. long, 6-12 mm. in diameter, truncate or obcordate (exceptionally broadly cuneate) at base a little dorsiventrally compressed and sulcate along both sutures (but more deeply so ventrally), passing distally into a deltoid or triangular-acuminate, laterally flattened, cuspidate beak, the ventral suture concave and the dorsal one (filiform but often undulate) strongly convex as viewed in profile the lateral angles plumply rounded, the thinly fleshy, green, glabrous valves becoming stramineous or brownish, delicately reticulate, inflexed below the unilocular beak as a complete septum 3-6 mm. wide, the endocarp also inwardly dilated along both sides of the seminiferous portion of the ventral suture to form hollow wings 0.5-1.2 mm. in diameter embracing the funicules, these becoming narrow, tubular cavities contained within the walls of the ripe fruit; seeds brown, sometimes purple-speckled, smooth, minutely punctate, or sparsely pitted, dull, 2-3.1 mm. long." (bibref: 1813).
Bloom Information
Bloom Color: White , Yellow , Purple , VioletBloom Time: Jun , Jul , Aug , Sep
Bloom Notes: "Petals whitish, perhaps sometimes faintly lilac-tinged, drying yellowish." (bibref: 1813).
Distribution
USA: CA , NVNative Distribution: "Along the west slope of the Sierra Nevada, California, from western Plumas County (Spanish Peak and vicinity) south to the Greenhorn Range (Baker Ridge) in the Kern Valley, southern Tulare County, extending east through Eldorado County to Lake Tahoe, and to Mount Rose, southern Washoe County, Nevada." (bibref: 1813).
Native Habitat: "Dry sandy or stony margins of meadows, mountain flats, lake shores, and openings in coniferous forest, mostly on granite, widely dispersed and locally plentiful between (5200, northward) 6500 and 10,000 (acc. Jepson 10,800) 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 bolanderi in USDA PlantsFNA: Find Astragalus bolanderi in the Flora of North America (if available)
Google: Search Google for Astragalus bolanderi
Metadata
Record Modified: 2020-12-07Research By: Joseph A. Marcus