Deseret milk-vetch (Astragalus desereticus)
Where Listed: WHEREVER FOUND
Deseret milk-vetch (Astragalus desereticus) is a perennial, herbaceous, almost stemless member in the bean family (Barneby 1989). Individual plants are 2–6 inches (in.) (5–15 centimeters (cm)) in height and arise from the base of an herbaceous stem. Stems are about 2 in. (5 cm) tall. The pinnately compound leaves (feather-like arrangement with leaflets on both sides of a central stalk) are 2–4 in. (5–10 cm) long with 11–17 leaflets. Leaflets are elliptical to ovate in shape, with a dense, silvery gray pubescence (short hairs) on both sides. Seed pods are 0.4–0.8 in. (1–2 cm) long and densely covered with lustrous hairs. The flower petals may be either completely white or whitish with pinkish wings and a lilac keel-tip.
- States/US Territories in which the Deseret milk-vetch is known to or is believed to occur: Utah
- US Counties in which the Deseret milk-vetch is known to or is believed to occur: View All
- Additional species information
|Status||Date Listed||Lead Region||Where Listed|
|10/20/1999||Mountain-Prairie Region (Region 6)|
» Federal Register Documents
|Date||Citation Page||Title||Document Type|
|04/18/2007||72 FR 19549 19551||Initiation of 5-Year Reviews of Seven Wildlife Species and Two Plant Species in the Mountain-Prairie Region||
|08/16/2011||Astragalus desereticus (Deseret Milk-vetch) 5-Year Review|
» Critical Habitat
No critical habitat rules have been published for the Deseret milk-vetch.
» Conservation Plans
No conservation plans have been created for Deseret milk-vetch.
» Life History
Deseret milk-vetch occurs in a sagebrush-juniper community (Welsh and Chatterley 1985). Species that are associated with Deseret milk-vetch are Pinus edulis (twoneedle pinyon), Juniperus osteosperma (Utah juniper), Quercus gambelii (Gambel oak), Artemisia tridentata (big sagebrush), Purshia tridentata (antelope bitterbrush), Opuntia polyacantha (plains pricklypear), Pseudoroegneria spicata (bluebunch wheatgrass), Achnatherum hymenoides (Indian ricegrass), Hesperostipa comata (needle and thread), and Eriogonum brevicaule (shortstem buckwheat) (Franklin 1990; Stone 1992; Humphrey 1993; UDWR et al. 2006). Bromus tectorum (cheatgrass) also was one of the main associated species in portions of the Deseret milk-vetch population (Humphrey 1993). Astragalus species are typically suited to moderately moist environments; their proliferation into drier climates and otherwise unfavorable microhabitats is a more recent phenomenon that has produced many geographically restricted genotypes, such as Deseret milk-vetch (Barneby 1989). In fact, Astragalus’ ability to colonize new unstable habitats in progressively dry climates has hastened the evolution of the genus (Barneby 1989).
Deseret milk-vetch likely reproduces sexually (Stone 1992). Flowering and seed set occur in May and June (Barneby 1989). We believe that small bees pollinate this plant based on the characteristics of the flower (Humphrey 1993). Fruiting occurs after successful pollination from June to July (USFWS 1991) and mature plants, defined as those greater than 4 in. (11 cm) in diameter, produced the most fruits with 6.4 38.7 fruits per mature plant (Humphrey 1993). Once the seed pods are mature, they fall off the plant and crack open at the tip to release the seeds. Seeds can remain dormant for a considerable time for many Astragalus spp. (Stone 1992; Humphrey 1993). This adaptation serves two functions: one is to optimize seedling survival, and the second is to spread germination over time so that a catastrophic event (such as drought or fire) does not kill all the seedlings. Germination trials indicate seed dormancy is broken by simple physical scarification (Dodge 2008). Another Astragalus species (A. barrii) occurs in erosive soils in which the moving rocks and soils scarify the seeds thereby breaking dormancy (Dingman 2005). This same process also could help break seed dormancy in Deseret milk-vetch.
Deseret milk-vetch is a short-lived perennial that occurs on steep, highly erosive soils (Stone 1992). Seedling mortality was high at one site (Humphrey 1993). Although we do not know how long Deseret milk-vetch may live for, the half-life of established plants within the genus Astragalus is 2.7 years (Stone 1992). That is to say, after 2.7 years, half of all individuals are dead. This species resembles Astragalus piutensis (Sevier milk-vetch) in habit, but is more loosely pubescent with mixed straightish and sinuous hairs with gray silvery foliage (Barneby 1989). Plants begin the active growing season shortly after snow melt in about mid April (Stone 1992). Toward the end of summer when it is hot and dry, the leaves closest to the ground die back. As the current season’s vegetative growth die back, new buds, at the soil level, form (Stone 1992). These buds generally survive the winter because they are protected from severe cold by snow cover (Stone 1992).
» Other Resources
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ITIS Reports -- ITIS (the Integrated Taxonomic Information System) is a source for authoritative taxonomic information on plants, animals, fungi, and microbes of North America and the world.
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