grass of Parnassus, (Parnassia), any of about 15 species of low perennial herbs, in the family Parnassiaceae, distributed throughout the Northern Hemisphere. The plants grow in tufts and bear white, greenish white, or yellow flowers. Five sterile stamens bearing nectar glands alternate with five fertile stamens in each flower. Grass of Parnassus is occasionally planted in damp, shady places near bodies of water.