Spiranthes from isolated wetlands in Santa Cruz and adjacent Cochise Counties, Arizona, which in the past have been cited as S. graminea Lindl., differ from that species in several floral and vegetative characters and in chromosome number; they are readily separated from it by their few-septate trichomes. The more northern S. diluvialis Sheviak is larger-flowered with more ringent flowers and different flower and sepal orientation. The morphological and cytological features of the Arizona plants indicate that they represent a distinct species, described here as S. delitescens Sheviak. The cytology of this species suggests an origin through hybridization and amphiploidy, but the parental species are not identified.