Cushenbury Milkvetch

Cushenbury milkvetch

Cushenbury milkvetch is endemic to the northeastern San Bernardino Mountains [9,12,16]. It is known from fewer than 33 occurrences from Furnace Canyon southeast to the head of Lone Valley, a range of 15 miles (24 km) [16]. In 1992, Cushenbury milkvetch populations were estimated at 5,000 to 10,000 individuals [16,17].

Distribution of Cushenbury milkvetch. Map courtesy of the Jepson Herbarium [11].

States [14]:
CA

Follow this link to the U.S. Forest Service Fire Effects Information Service to see a table with fire regime information that may be relevant to habitats in which this species occurs

More info for the terms: cactus, cover, forb, formation, herb, seed, tree, vine, woodland

Forb INFORMATION AVAILABLE:
In October of 2012 an extensive search was done to locate information on Cushenbury milkvetch (see FEIS's list of source literature), with few results. The following paragraphs provide details of the available information.
DISTRIBUTION AND OCCURRENCE SPECIES: Astragalus albens GENERAL DISTRIBUTION:
Cushenbury milkvetch is endemic to the northeastern San Bernardino Mountains [9,12,16]. It is known from fewer than 33 occurrences from Furnace Canyon southeast to the head of Lone Valley, a range of 15 miles (24 km) [16]. In 1992, Cushenbury milkvetch populations were estimated at 5,000 to 10,000 individuals [16,17].

Distribution of Cushenbury milkvetch. Map courtesy of the Jepson Herbarium [11]. States [14]:
CA SITE CHARACTERISTICS:
Cushenbury milkvetch occurs on gentle, rocky slopes and canyon washes composed of limestone and dolomite (carbonate) soils at elevations of 5,000 to 6,600 feet (1,500-2,000 m) [6,16,17]. A few occurrences are found below 5,000 feet in rocky drainages that receive limestone outwash from higher drainages [17]. Populations of Cushenbury milkvetch have also been documented on granitic soils [12,16]. Cushenbury milkvetch prefers an open canopy, rock cover greater than 75%, and 21.3% calcium [3,6] and little accumulation of organic material [3,6,16,17] in the soil.

PLANT COMMUNITIES:
Cushenbury milkvetch grows in Joshua tree (Yucca brevifolia) woodland, singleleaf pinyon-Utah juniper (Pinus monophylla-Juniperus osteosperma) woodland, and Mojavean desert scrub [2,12]. Plant species commonly associated with Cushenbury milkvetch plants in the carbonate habitats are Utah juniper, singleleaf pinyon, Joshua tree, curlleaf mountain-mahogany (Cercocarpus ledifolius), blackbrush (Coleogyne ramosissima), Mojave mound cactus (Echinocereus mojavensis), desert almond (Prunus fasciculata), Mojave yucca (Yucca schidigera), sand dropseed (Sporobolus cryptandrus), and desert needlegrass (Achnatherum speciosum) [3]. Cushenbury milkvetch often occurs with 2 other federally listed species, Cushenbury buckwheat (Eriogonum ovalifolium var. vineum) and Parish’s daisy (Erigeron parishii) [16].

The scientific name of Cushenbury milkvetch is Astragalus albens Greene (Fabaceae) [11].

Endangered [15]

State legal status: S1, Critically imperiled. [2]

Hamosa albens (Greene) Rydb. Bull. Torrey Club 54:22. 1927.
Astragalus albens Greene, Bull. Calif. Acad. 1: 156. 1885.
A perennial, with a deep root and short eaudex; stems many, decumbent or spreading, 2-5 dm. long, strigose with white hairs, flexuose; leaves 3-6 cm. long, spreading; stipules deltoid, 3-4 mm. long, sparingly strigose; leaflets 7-11, broadly obovate, 5-10 mm. long, silvery on both sides, mostly rounded at the apex; peduncles 3-5 cm. long; racemes elongate, about as long; bracts subulate, 1 mm. long; pedicels 1-1.5 mm. long; calyx silvery, the tube 2 mm. long, the teeth subulate, 1 mm. long; corolla purple, about 8 mm. long; banner broadly obovate, abruptly arcuate; wings shorter, the blade obliquely oblanceolate; keel-petals nearly as long as the banner, the blade very broad, strongly arcuate at the rounded apex; pod arcuate, silvery, acute at each end, 1.5-2 cm. long, about 3.5 mm. wide, and 2 mm. thick, white-strigose, deeply sulcate on the lower suture, narrowly cordate in cross-section.
Type locality: Mohave Desert. Distribution: Mohave and Colorado deserts.

Annual, Herbs, Taproot present, Nodules present, Plants stoloniferous, Stems prostrate, trailing, or mat forming, Stems less than 1 m tall, Stems solid, Stems or young twigs sparsely to densely hairy, Stems silvery, canescent, tomentose, cobwebby, or wooly, Stems with 2-branched hairs, dolabriform, Leaves alternate, Leaves petiolate, Stipules conspicuous, Stipules membranous or chartaceous, Stipules persistent, Stipules free, Leaves compound, Leaves odd pinnate, Leaf or leaflet margins entire, Leaflets opposite, Leaflets 5-9, Leaves hairy on one or both surfaces, Inflorescences racemes, Inflorescence axilla ry, Inflorescence or flowers lax, declined or pendulous, Bracts very small, absent or caducous, Flowers zygomorphic, Calyx 5-lobed, Calyx glabrous, Petals separate, Corolla papilionaceous, Petals clawed, Petals pinkish to rose, Petals blue, lavander to purple, or violet, Banner petal narrow or oblanceolate, Wing petals narrow, oblanceolate to oblong, Wing tips obtuse or rounded, Keel petals auriculate, spurred, or gibbous, Keel tips obtuse or rounded, not beaked, Stamens 9-10, Stamens diadelphous, 9 united, 1 free, Filaments glabrous, Style terete, Style persistent in fruit, Fruit a legume, Fruit stipitate, Fruit tardily or weakly dehiscent, Fruit oblong or ellipsoidal, Fruit strongly curved, falcate, bent, or lunate, Fruit exserted from calyx, Fruit beaked, Fruit hairy, Fruit 3-10 seeded, Seeds cordiform, mit-shaped, notched at one end, Seed surface smooth, Seeds olive, brown, or black.

Astragalus albens is a species of milkvetch known by the common names Cushenbury milkvetch and silvery-white milkvetch.