This tiny member of the pea family with minute pale purple flowers favors very specific habitats at the canyon's edge. Listed as endangered in 1990, sentry milk-vetch is at risk of extinction because the plant exists in just three populations in very small numbers.

The 2006 Sentry Milk-vetch Recovery Plan prepared by the U.S. Fish and Wildlife Service called for a number of major actions to be implemented in order to protect the species, including establishing a refuge greenhouse (ex situ) population, conducting ecological studies of the plant’s habitat requirements, surveying potential habitat to see if other populations exist, and establishing new populations to meet recovery goals.

Read more of this Canyon Sketches article here: http://www.nps.gov/grca/naturescience/cynsk-v16.htm