Asa Gray first named this species Astragalus cooperi in honor of William Cooper (1798-1864), noted American naturalist and discoverer of the species (Gray 1859). He was one of the founders of the New York Lyceum of Natural History (later the New York Academy of Sciences), and the first American member of the Zoological Society of London. The Cooper's hawk is named after him (Wikipedia contributors) and he was the person who, in 1830, discovered Hart's-tongue fern at Chittenango Falls.
There are three existing populations that have fewer than 50 plants each. There are 23 historical locations, mostly known from the late 1800s and early 1900s up to 1942. Most of these locations have either not been searched in detail for this species or have been extirpated.
Existing populations are small and threatened by invasive species.
It looks like there has been a substantial decline in populations over the last 100 years. There have been recent botanical inventories in the areas where there are historical populations and no plants have been found. Many of the limestone areas where this plant occurred have been taken over by black swallow-wort and other invasives.
One population is threatened by black swallow-wort, as are many of the limestone areas with historical records of Cooper's Milkvetch.
Infestations of exotic invasive species should be suppressed around known populations.
Research is needed to see if populations can be augmented at known sites.
In New York, milk vetch is known from shale cliffs and deep ravines with rich,calcareous forests, with a single historical record from a lakeside shale cliff (New York Natural Heritage Program 2013). River banks and lakeshores, especially on limestone (Gleason & Cronquist 1991). Marshy to dry open, sometimes rocky, clearings, shores, thickets, and river banks; often in calcareous sites (Voss 1985). Calcareous gravels, talus and cliffs (Fernald 1970).
Astraglus occurs along the limestone belt of central and western New York, east from Oneida County and west to Erie County.
Cooper's milkvetch is found from MA and NY in the east, west as along the upper midwest as far as Manitoba and the Dakotas, and south to Virginia.
Astragalus neglectus is an erect perennial with hollow branching stems, growing in clusters up to 90 cm tall from the crown of a taproot. The stems are nearly smooth (glabrous) or with only simple hairs and not rhizomatous. The leaves are pinnately compound with 10 to 23 leaflets each. The flowers are shaped like pea flowers, white or tinged with violet, and 1.2 to 1.4 cm long with a short basal ear-shaped appendage (auricle). They are borne in lax racemes (clusters) on stalks which are either shorter than or barely exceeding their subtending leaves. The fruit are erect, one-chambered pods, borne sessilely from a calyx covered in black hairs. The pods themselves are inflated, egg-shaped, and 1.5 to 2 cm long with short beaks (Fernald 1950).
Astragalus neglectus is an erect perennial with hollow branching stems, growing in clusters up to 90 cm tall from the crown of a taproot. The stems are nearly smooth (glabrous) or with only simple hairs and not rhizomatous. The leaves are pinnately compound with 10 to 23 leaflets each. The flowers are winged, tubular (pea-like), white or tinged with violet and 1.2 to 1.4 cm long with a short basal ear-shaped appendage (auricle). They are borne in lax racemes (clusters) on stalks (peduncles) either shorter than or barely exceeding their subtending leaves. The fruit are erect, one-chambered legume pods, borne sessilely in a cup-like structure (calyx) covered with black hairs. The glabrous pods are inflated with a short beak, egg-shaped, and 1.5 to 2 cm long, by 1 to 1.4 cm thick (Fernald 1950).
A complete plant with roots, leaves and either fruit or flowers is needed for a positive identification.
Only two other Astragalus species are reported from New York (A. canadensis and A. glycyphyllos). The fruit of both A. canadensis and A. glycyphyllos are two-chambered (bilocular), and scarcely inflated, in contrast to the inflated unilocular pods of A. neglectus. A. neglectus may also appear similar to species of the genus Vicia, but these species can be distinguished by their uninflated more pea-like fruits.
Astragalus neglectus typically flowers from June through mid-July, with fruits persisting nearly to the first frost.
The time of year you would expect to find Cooper's Milkvetch flowering and fruiting in New York.
Astragalus neglectus (Torr. & Gray) Sheldon
Fernald, M.L. 1950. Gray's manual of botany. 8th edition. D. Van Nostrand, New York. 1632 pp.
Barneby, R.C. 1964. Atlas of North American Astragalus. 2 Vols. New York Botanical Garden, Bronx, New York. 1188 pp.
Coffin, B., and L. Pfannmuller, eds. 1988. Minnesota's endangered flora and fauna. Univ. Minnesota Press, Minneapolis. 473 pp.
Gleason, H.A., and A. Cronquist. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. New York Botanical Garden, Bronx, New York. 910 pp.
Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.
Great Plains Flora Association (R.L. McGregor, coordinator; T.M. Barkley, ed., R.E. Brooks and E.K. Schofield, associate eds.). 1986. Flora of the Great Plains. University Press of Kansas, Lawrence, Kansas. 1392 pp.
Holmgren, Noel. 1998. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York.
Hutton, E.E. Jr. 1989. Four western plants new to West Virginia. Castanea 54(3):203-207.
McCance, R.M., Jr., and J.F. Burns, eds. 1984. Ohio endangered and threatened vascular plants: Abstracts of state-listed taxa. Division Natural Areas and Preserves, Ohio Dept. Natural Resources, Columbus. 635 pp.
Mitchell, Richard S. and Gordon C. Tucker. 1997. Revised Checklist of New York State Plants. Contributions to a Flora of New York State. Checklist IV. Bulletin No. 490. New York State Museum. Albany, NY. 400 pp.
New York Natural Heritage Program. 2010. Biotics database. New York Natural Heritage Program. New York State Department of Environmental Conservation. Albany, NY.
New York Natural Heritage Program. 2020. New York Natural Heritage Program Databases. Albany, NY.
Reschke, Carol. 1990. Ecological communities of New York State. New York Natural Heritage Program, New York State Department of Environmental Conservation. Latham, NY. 96 pp. plus xi.
Scoggan, H.J. 1978-1979. The flora of Canada: Parts 1-4. National Museums Canada, Ottawa. 1711 pp.
Voss, E.G. 1985. Michigan Flora. Part II. Dicots (Saururaceae - Cornaceae). Cranbrook Institute of Science and University of Michigan Herbarium. Ann Arbor, Michigan. 724 pp.
Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://newyork.plantatlas.usf.edu/, Albany, New York
This guide was authored by: Stephen M. Young, Elizabeth Spencer, Richard M. Ring.
Information for this guide was last updated on: April 2, 2013
Please cite this page as:
New York Natural Heritage Program. 2020. Online Conservation Guide for Astragalus neglectus. Available from: https://guides.nynhp.org/coopers-milkvetch/. Accessed July 9, 2020.