Cooper's Milkvetch (Astragalus neglectus)

Life history

Species overview

Cooper's Milkvetch (Astragalus neglectus), a Wisconsin Endangered plant, is found in the woodland-prairie ecotone as well as on riverbanks, ravines, and lakeshores, especially on dolomite near Lake Michigan. Blooming occurs throughout June; fruiting occurs throughout July. The optimal identification period for this species is early June through late July.

Synonyms: Astragalus cooperi, Phaca neglecta

Identification

• Distinguishing characteristics: Flowers and fruits borne barely above the tallest leaves; stem and leaves with simple hairs; stipules free (not joined around stem as in A. canadensis); fruit sessile, thick and inflated (8 to 18 mm wide) containing a single chamber inside.
• Flower characteristics: Inflorescence several racemes barely extending past tallest leaves; flowers white, 11 to 15 mm long.
• Fruit characteristics: Sessile, erect, and spindle- or obliquely egg-shaped, 2 cm x 8 to 18 mm, and inflated like a bladder, unilocular.
• Leaf characteristics: Pinnately compound leaves contain 11 to 23, oblong to elliptic leaflets that are 1 to 3 cm long, underside covered in many straight, stiff, and sharp hairs that are pressed flat against the leaves; stipules subtending the leaves free.

Phenology

• Blooming phenology: throughout June
• Fruiting phenology: throughout July
• Optimum time to identify: The optimal identification period for this species is early June through late July

Other

• Growth form: Forb-erect
• Vegetative reproduction:
• Life cycle: Perennial
• Comments: Associated Species: Not recorded for Wisconsin populations.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - state and federal - and the rank (S and G Ranks) for Cooper's Milkvetch (Astragalus neglectus). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Habitats and landscapes

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

General habitat information

• Habitat description: Found in the woodland-prairie ecotone as well as on riverbanks, ravines, and lakeshores, especially on dolomite near Lake Michigan.
• Soils: Calcareous soils.

Natural communities

This table lists the natural communities that are associated with Cooper's Milkvetch. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).

Ecological landscapes

This table lists the ecological landscape association scores for Cooper's Milkvetch. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

Species guidance

The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.

Avoidance measures

These are specific actions designed to avoid "take" (mortality) of this species.

• Avoid broadcast spraying of herbicides; use care with spot spraying.
• Avoid locating landings, staging areas, or access routes in open sandy areas dominated by native grasses.
• Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.

Management guidance

Management guidelines are additional considerations that may help maintain or enhance habitat for this species

• Although this species appears to require intermittent soil disturbance, silvicultural techniques which result in frequent soil disturbance and the loss of propagules from the population should be avoided.
• Maintain partial canopy to encourage woodland species; avoid closed-canopy conditions.
• Prescribed burns and/or brushing may be beneficial (dependent on local site conditions).

Other resources

Links to additional Cooper's Milkvetch information

Other links related to vascular plants (all exit the DNR website)

• Wisconsin Flora
• NatureServe Explorer
• Atlas of Wisconsin Prairie and Savanna Flora - Wisconsin State Herbarium
• USDA - NRCS Plants Database
• USGS Midwestern Wetland Flora - field office guide to plant species
• eFloras
• Cofrin Center for Biodiversity Herbarium
• Intermountain Herbarium Grasses of North America
• Orchids of Wisconsin

Photos

Click to view a larger version. Please considering donating a photo to the Natural Heritage Conservation Program for educational uses. Photo use