Platanthera ephemerantha
White-flowered rein-orchid
(c) Nicholas Wei, some rights reserved (CC BY-SA) · licence
Family: Orchidaceae · Type: Herb · Native
Conservation status: CNPS 1B.2
Platanthera ephemerantha (White-flowered rein-orchid) is a native California herb in the Orchidaceae family, recognized by unique white perianth distinguishes from all green-flowered congeners.
White-flowered rein-orchid is a California native found in the Northwestern California and southwestern San Francisco Bay Area bioregions, growing in open to shady sites within conifer and mixed-evergreen forest below 1,500 meters. Flowering from May to September, it produces a somewhat one-sided, congested to open inflorescence of white flowers with a faint green midvein, an ovate recurved lip 1.5 to 4 millimeters long, and a downward-pointed spur.
Identification and appearance
Key characters: 8 sympatric species; unique white perianth distinguishes from all green-flowered congeners
Habitat and range
Habitat: Open to shady sites, conifer and mixed-evergreen forest
Elevation: < 1500 m
California counties: Humboldt, Del Norte, Trinity, Santa Cruz, Mendocino, San Mateo, Sonoma
Outside California: to Alaska
Bloom period
Platanthera ephemerantha blooms May--Sep.
Conservation status
CNPS 1B.2
How to tell it apart
vs Listera: Piperia flowers have obvious backward spurs; Listera flowers lack spurs entirely.; vs Platanthera: Piperia is leafless at flowering with dense spikes; Platanthera has leafy stems when blooming.; vs Epipactis: Piperia has tight cylindrical spikes of tiny spurred flowers; Epipactis has loose rows of larger spurless flowers.; vs Goodyera: Piperia is leafless when flowering; Goodyera has distinctive white-veined evergreen leaves present at bloom.; vs Spiranthes: Piperia flowers have backward spurs in straight spikes; Spiranthes lacks spurs and flowers spiral up stem.
Frequently asked questions
Is Platanthera ephemerantha native to California?
Yes. Platanthera ephemerantha is native to California (recorded as native).
When does Platanthera ephemerantha bloom?
Platanthera ephemerantha blooms May--Sep.
Where in California does Platanthera ephemerantha grow?
Platanthera ephemerantha occurs in Humboldt, Del Norte, Trinity, Santa Cruz, Mendocino, San Mateo, Sonoma, at elevations of < 1500 m.
What plant family does Platanthera ephemerantha belong to?
Platanthera ephemerantha is in the Orchidaceae family, genus Platanthera.
Is Platanthera ephemerantha rare or endangered?
Platanthera ephemerantha carries California Rare Plant Rank 1B.2, state rank S3.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.