Olsynium douglasii is a species of flowering plant in the iris family (Iridaceae). Common names include Douglas' olsynium, Douglas' grasswidow, grass-widow, blue-eyed grass, purple-eyed-grass, and satin flower, It is the only species in the genus Olsynium in North America, the remaining 11 species being from South America. It was formerly treated in the related genus Sisyrinchium. Despite the common names, it is not a true grass (Poaceae).