Page author: David Giblin
Platanthera transversa
royal rein orchid

Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to California.

Habitat: Forest understory from low to middle elevations.

Flowers: May-August

Origin: Native

Conservation Status: Not of concern


Herbaceous perennials, 12-57 cm tall, terrestrial, erect to slightly decumbent, somewhat succulent, glabrous; stems not angled, unbranched, swollen at base; roots few, fasciculate, slender and tuberous, fleshy.


Leaves 2-6, prostrate, basal, ephemeral; blades sessile, lanceolate to oblanceolate, 6-19 mm long and 1-4.5 cm broad; cauline bracts ovate to linear-lanceolate.


Inflorescence densely flowered spike or raceme, 3.5-32 cm, rachis approximately same length as peduncle, bracts 3-15; flowers resupinate, whitish with pale green to light yellowish green midvein, fragrance strong, emits nocturnally, clove-like; sepals 2.5-4.5 mm long and 1-2 mm broad; dorsal sepal extending forward between petals, oblong to lanceolate; lateral sepals bending backward to spreading, oblong-lanceolate; petals bending backward to spreading, oblique to sickle-shaped, oblong, 2-5 mm long ad 1-2 mm broad; labellum straight to bent slightly downward, oblong to ovate-elliptic, 2.2-5.3 mm long and 1-2.5 mm broad, midrib thickened; spur horizontal or nearly so, not curved, 7-12 mm; column short with no auricles; anther 1, erect; pollinaria 2; pollinia 2, sectile; caudicles not easily seen, attached to viscidia; viscidia oblong, 0.5-0.7 mm long and 0.2-0.3 mm broad; stigmas confluent and concave; rostellum blunt, 3-lobed;.


Capsules 4-13 mm, ellipsoid to cylindric, erect, nearly sessile; seeds cinnamon-brown.

Accepted Name:
Platanthera transversa (Suksd.) R.M. Bateman
Publication: Botanical Journal of the Linnean Society 142(1): 21. 2003.

Synonyms & Misapplications:
Piperia transversa Suksd. [FNA26]
Additional Resources:

PNW Herbaria: Specimen records of Platanthera transversa in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Platanthera transversa checklist entry.

E-Flora BC: Platanthera transversa atlas page.

CalPhotos: Platanthera transversa photos.

USDA Plants: Platanthera transversa information.

24 photographs:
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