Parnassiaceae

Parnassiaceae is a small family of flowering plants in the order Ranunculales. It includes two genera, Parnassia and Oreonana, comprising a few dozen species in total. In many modern classifications it is treated as a distinct family, though earlier systems sometimes placed Parnassia as a subfamily within Papaveraceae.

Members of Parnassiaceae are herbaceous perennials with creeping rhizomes. They typically have basal leaves and produce one or more flowers on slender flowering stalks. The flowers are generally showy and range in color from white to pale green or pink. They possess petaloid components and numerous stamens surrounding a central pistil, and are primarily insect-pollinated.

The genus Parnassia is widespread across cool temperate regions of the Northern Hemisphere, occurring in parts of Europe, Asia, and North America. Oreonana is a smaller, North American genus with a more restricted distribution, mainly in western regions. Habitats are usually moist and cool, including wetlands, stream banks, bogs, and alpine or subalpine meadows.

Taxonomically, Parnassiaceae is closely related to Papaveraceae within Ranunculales. Phylogenetic studies support recognizing it as a separate family in modern classifications, even though historical systems sometimes treated it as part of Papaveraceae.

Etymology-wise, the name Parnassiaceae derives from the genus Parnassia, which is named for Mount Parnassus in Greek mythology. The common name grass-of-Parnassus refers to the graceful, grass-like habit of some species.

See also: Papaveraceae, Ranunculales.