Page authors: Don Knoke, David Giblin
Platanthera orbiculata
large round-leaf orchid
Specimens
Photos

Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to Oregon, east across Canada and the northern U.S. to the Atlantic Coast, also in the southeastern U.S.

Habitat: Moist, mossy forests.

Flowers: June-August

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Self-pollination, flies

Description:
General:

Glabrous, scapose perennial 2-6 dm. tall.

Leaves:

Leaves usually 2, opposite and basal, subsessile, spreading and usually lying on the ground, fleshy, suborbicular to oblong-elliptic, 6-16 cm. long and 3-14 cm. wide, rounded; scape usually with 1-3 small bracts about midlength.

Flowers:

Inflorescence a loose raceme with floral bracts 7-12 mm. long, green, linear to lanceolate; flowers 5-25, pale to deep greenish-white or yellowish, with pedicles 3-7 mm. long; upper sepal erect, reniform to broadly ovate, 4-8 mm. long and broad, rounded, entire to shallowly lobed near the tip; lower sepals obliquely triangular-ovate, slightly reflexed, 8-13 mm. long; petals paler than the sepals, often nearly white, narrower and shorter than the lower sepals, rounded, reflexed; lip white, strap-shaped, pendant, slightly upturned at the tip, 2-4 mm. broad and 10-20 mm. long; spur club-shaped, strongly curved, 15-25 mm. long, pale and translucent near the base, the tip greenish; stamens and style fused to form a column 4-5 mm. long with 2 lateral projections 3-5 mm. long.

Accepted Name:
Platanthera orbiculata (Pursh) Lindl.
Publication: Gen. Sp. Orchid. Pl. 286. 1835.

Synonyms & Misapplications:
Habenaria orbiculata (Pursh) Torr. [HC]
Orchis orbiculata Pursh
Additional Resources:

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

WA Flora Checklist: Platanthera orbiculata checklist entry

OregonFlora: Platanthera orbiculata information

E-Flora BC: Platanthera orbiculata atlas page

CalPhotos: Platanthera orbiculata photos

42 photographs:
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