INDIANAPOLIS (AP) – A mustard plant known to grow in Indiana only along a Posey County roadside is now protected under the Endangered Species Act.

The U.S. Fish and Wildlife Service announced recently it was adding Short's Bladderpod to the list. State botanist Mike Homoya says scientists don't know why the plant grows in southwest Indiana. He says the nearest populations are more than 200 miles away in the bluegrass region of Kentucky and around Nashville, Tennessee, where it grows on limestone bedrock along streams.  

It grows on clay in Posey County, where it was first spotted in 1941. Homoya says how well it grows depends on how often other vegetation is cleared.

 Short's Bladderpod is the third Indiana plant to be listed as federally endangered, joining Short's goldenrod and running buffalo clover.