Astragalus tennesseensis

Plants (5–)10–50 cm, pilose to pilose-hirsute. Stems decumbent to ascending, densely pilose to pilose-hirsute. Leaves (6–)8–15 cm; stipules often connate-sheathing at proximal nodes, connate or distinct at distal nodes, 5–20 mm, submembranous becoming papery-scarious; leaflet blades oblong-elliptic or obovate-obcordate, (4–)6–23 mm, apex obtuse, emarginate, or apiculate-acute, surfaces sparsely pilose or pilose-hirsute abaxially, glabrous adaxially. Peduncles incurved-ascending, 5–10(–14) cm. Racemes 9–20-flowered; axis 2–5(–6) cm in fruit; bracts 5–12 mm; bracteoles 0. Pedicels 1.5–3.5 mm. Flowers 14–19 mm; calyx 8.3–15.1 mm, sparsely white-hirsute, tube gibbous-saccate behind pedicel, 5.9–11.4 mm, lobes lanceolate-subulate, 2.4–4 mm; corolla whitish or pale cream, drying yellow, immaculate; keel 11–13.6 mm. Legumes green or pink-tinged becoming stramineous, 25–40 × 7–13 mm, fleshy becoming spongy, walls 2.5–3 mm thick, translucent, alveolate-rugulose, sparsely hirsute; gynophore stout, (1–)1.3–2 mm, glabrous.

Phenology: Flowering Apr–Jun.
Habitat: Openings in cedar barrens, edges of thickets, on limestone pavement, stony calcareous hillsides.
Elevation: 200–300 m.

Ala., Ill., Tenn.

Discussion

Astragalus tennesseensis is the only species of the genus between the Mississippi River and the Appalachian Mountains with pilose indumentum (D. Isely 1998). It is locally abundant on the cedar glades of middle Tennessee, but many of these unique communities have been lost in recent decades due to the rapid growth of metropolitan Nashville. Extant populations also occur in Lawrence and Morgan counties in northern Alabama and Tazewell County in central Illinois. It has been extirpated from four counties in Illinois, from its only known site in Indiana, from one county in Tennessee, and from one county in Alabama (J. M. Baskin and C. C. Baskin 2005).

Astragalus tennesseensis is in the Center for Plant Conservation’s National Collection of Endangered Plants.

Selected References

None.

Lower Taxa