Astragalus bibullatus

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Pyne's ground plum
Plant Info
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Fabales
Family: Fabaceae
Subfamily: Faboideae
Tribe: Galegeae
Genus: Astragalus
Species: A. bibullatus

Binomial name
Astragalus bibullatus
Barneby and E.L. Bridges

Astragalus bibullatus (Pyne's ground plum) is an endangered species that is endemic to the cedar glades of the central basin of Tennessee. It is found in only about five populations located within a few kilometers of each other in Rutherford County, Tennessee.

The common name refers to Milo Pyne, who discovered the species in the 1980's, and the odd-looking smooth, purplish fruits that ripen on the ground in June and look superficially like plums. However, the species is a legume and is unrelated to the plum. The foliage of A. bibullatus looks similar to the more widespread cedar glade endemic, A. tennessensis. However, the flowers of A. bibullatus are pinkish purple in contrast to the white flowers of A. tennessensis. The fruits are also quite different. A. tennessensis fruits are greenish, hairy, and are more elongated as is more typical for legumes.

Threats

Because of the small number of populations, A. bibullatus is threatened by habitat destruction. One population is now protected in the Flat Rock Cedar Glade and Barrens State Natural Area. Because there is very little genetic differentiation among populations [1], further loss of genetic variabliliy is not a threat.

References

Barneby, R.D. and E.L. Bridges. 1987. A new species of Astragalus (Fabaceae) from Tennessee's Central Basin. Brittonia 39:358-363.

Baskauf, C. J. and S. Snapp. 1998. Population genetics of the cedar-glade endemic Astragalus bibullatus (Fabaceae) using isozymes. Annals of the Missouri Botanical Garden 85: 90-96.

Morris, A. B., R. S. Baucom, and M. B. Cruzan. 2002. Stratified anyalysis of the soil seed bank in the cedar glade endemic Astragalus bibullatus: evidence for historical changes in genetic structure. American Journal of Botany 89: 29-36.

External links