Astragalus robbinsii var. jesupi NatureServe Explorer Species Reports — NatureServe Explorer is a source for authoritative conservation information on more than 50,000 plants, animals and ecological communtities of the U.S and Canada. NatureServe Explorer provides in-depth information on rare and endangered species, but includes common plants and animals too. NatureServe Explorer is a product of NatureServe in collaboration with the Natural Heritage Network.
FWS Digital Media Library — The U.S. Fish and Wildlife Service’s National Digital Library is a searchable collection of selected images, historical artifacts, audio clips, publications, and video.Jesup’s milk-vetch, Astragalus robbinsii var. jesupi, is a perennial herb with featherlike compound leaves; each oblong or elliptical leaflet is only 0.4-0.8 in (1-2 cm long. Several slightly hairy stems, 8-24 in (20-60 cm) tall, grow from a woody rhizome.
Violet to bluish-purple flowers appear in late May or early June. The fruit is a flattened tapered pod. The form of the pod is important in differentiating among the three New England varieties of A. robbinsii. Of the other varieties, A. robbinsii var. robbinsii is now extinct, and var. minor is very rare in New England.Jesup’s milk-vetch prefers rocky bluffs along river banks, where it roots securely in silt-filled cracks of calcareous bedrock outcrops. Spring flooding annually scours the rock surfaces, ridding the milk-vetch of its competitor plants and depositing fertile soil. Shade provided by the mature hard-wood trees along the river bank is an important factor in the plant’s survival.
