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Western Wetland Flora

Field Office Guide to Plant Species

Leafy White Orchid
Platanthera dilatata (Pursh) Lindl. ex Beck

JPG -- Species Photo JPG -- Distribution Map

Family: Orchid (Orchidaceae)
Flowering: June-September
Field Marks: This orchid has white or greenish white flowers, with the spur at least half as long as the lip petal. There are up to 12 lanceolate leaves on the stem.
Habitat: Bogs, along streams, in marshes, wet meadows.
Habit: Perennial herb with slender, fleshy roots.
Stems: Upright, slender to stout, smooth, up to 3 feet tall.
Leaves: Alternate, simple, up to 12 per stem, narrowly lanceolate to lanceolate, rounded to pointed at the tip, tapering to the base, smooth, up to 12 inches long, up to 2 1/2 inches wide.
Flowers: Several in racemes, fragrant, white to greenish white.
Sepals: 3, one of them forming a hood with the petals, up to 1/3 inch long, the other 2 elliptic to lanceolate, up to nearly 1/2 inch long.
Petals: 3, narrowly to broadly lanceolate, up to 1/3 inch long, the lip petal up to 1/2 inch long, up to 1/4 inch wide; spur more than half as long to as long as the lip petal.
Stamens: 1.
Pistils: Ovary inferior.
Fruits: Capsules ellipsoid, 1/3-1/2 inch long, up to 1/6 inch wide.
Notes: There is variation in the color of the flower and the length of the spur. The earlier frequently used name for this orchid was Habenaria dilatata.

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U.S. Department of the Interior | U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/plants/florawe/species/4/platdila.htm
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Page Last Modified: Saturday, 02-Feb-2013 06:25:19 EST
Reston, VA [vaww55]