Summary

Did you know?

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.

State Ranking Justification

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.

Short-term Trends

Existing populations are small and threatened by invasive species.

Long-term Trends

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.

Conservation and Management

Threats

One population is threatened by black swallow-wort, as are many of the limestone areas with historical records of Cooper's Milkvetch.

Conservation Strategies and Management Practices

Infestations of exotic invasive species should be suppressed around known populations.

Research Needs

Research is needed to see if populations can be augmented at known sites.

Habitat

Habitat

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).

Associated Ecological Communities

• Calcareous cliff community* (guide)
  A community that occurs on vertical exposures of resistant, calcareous bedrock (such as limestone or dolomite) or consolidated material; these cliffs often include ledges and small areas of talus.
• Calcareous talus slope woodland* (guide)
  An open or closed canopy community that occurs on talus slopes composed of calcareous bedrock such as limestone or dolomite. The soils are usually moist and loamy; there may be numerous rock outcrops.
• Hemlock-northern hardwood forest (guide)
  A mixed forest that typically occurs on middle to lower slopes of ravines, on cool, mid-elevation slopes, and on moist, well-drained sites at the margins of swamps. Eastern hemlock is present and is often the most abundant tree in the forest.
• Maple-basswood rich mesic forest (guide)
  A species rich hardwood forest that typically occurs on well-drained, moist soils of circumneutral pH. Rich herbs are predominant in the ground layer and are usually correlated with calcareous bedrock, although bedrock does not have to be exposed. The dominant trees are sugar maple, basswood, and white ash.
• Shale cliff and talus community (guide)
  A community that occurs on nearly vertical exposures of shale bedrock and includes ledges and small areas of talus. Talus areas are composed of small fragments that are unstable and steeply sloping; the unstable nature of the shale results in uneven slopes and many rock crevices.

* probable association but not confirmed.

Associated Species

• Acer saccharum (sugar maple)
• Anemone virginiana (tall anemone, thimbleweed)
• Carex eburnea (bristle-leaved sedge)
• Ceanothus americanus (New Jersey-tea)
• Juniperus virginiana
• Lathyrus ochroleucus (pale vetchling)
• Liriodendron tulipifera (tulip tree, tulip poplar, yellow poplar)
• Ostrya virginiana (hop hornbeam, ironwood)
• Packera obovata (round-leaved ragwort)
• Pedicularis canadensis (wood-betony, eastern lousewort)
• Pycnanthemum incanum
• Rhus aromatica
• Rubus odoratus (purple-flowering raspberry)
• Tilia americana
• Viburnum acerifolium (maple-leaved viburnum)
• Viburnum rafinesquianum

Range

New York State Distribution

Astraglus occurs along the limestone belt of central and western New York, east from Oneida County and west to Erie County.

Global Distribution

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.

Identification Comments

General Description

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).

Identifying Characteristics

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).

Best Life Stage for Proper Identification

A complete plant with roots, leaves and either fruit or flowers is needed for a positive identification.

Similar Species

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.

Best Time to See

Astragalus neglectus typically flowers from June through mid-July, with fruits persisting nearly to the first frost.

Cooper's Milkvetch Images

Taxonomy

Cooper's Milkvetch
Astragalus neglectus (Torr. & Gray) Sheldon

• Kingdom Plantae
  • Phylum Anthophyta
    • Class Dicotyledoneae (Dicots)
      • Order Fabales
        • Family Fabaceae (Pea Family)

Additional Common Names

• Cooper Milk-vetch
• Milk-vetch

Synonyms

• Astragalus cooperi A. Gray
• Phaca neglecta Torrey & A. Gray

Additional Resources

Best Identification Reference

Fernald, M.L. 1950. Gray's manual of botany. 8th edition. D. Van Nostrand, New York. 1632 pp.

Other References

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. 2023. 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

Links

• Conservation Assessment of Cooper's Milkvetch - USDA Forest Service Eastern Region
• Google Images
• NatureServer Explorer
• NY Flora Atlas
• USDA Plants Database

About This Guide

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. 2023. Online Conservation Guide for Astragalus neglectus. Available from: https://guides.nynhp.org/coopers-milkvetch/. Accessed September 24, 2023.