Eleven plant species listed as threatened in the United States 'statutes are found in the park; Palmer amsonia Amsonia palmeri, goldenweed Haplopappus salicinus, Draba asprella var. kaibensis, plains cactus Pediocactus bradyi, scouler catchfly Silene rectiramea, phacelia Phacelia filiformis, wild buckwheats Eriogonum darrovii, E. thompsonae var. atwoodi and E. zionis var. coccineum, primrose Primula hunnewellii and clute penstemon Penstemon clutei.    From Wordnik.com.  [Grand Canyon National Park, United States] Reference