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Northeast Wetland Flora

Field Office Guide to Plant Species

Pink Lady's-slipper
Cypripedium acaule Ait.

JPG -- Species Photo JPG -- Distribution Map

Family: Orchid (Orchidaceae)
Flowering: April-July
Field Marks: This is the only lady's-slipper orchid that has a leafless flowering stalk with 2 leaves at the base of the plant and a rosy-pink lip petal.
Habitat: Bogs, wet woods, acid woodlands.
Habit: Perennial herb with thick, fibrous roots.
Stems: Upright, unbranched, leafless, up to 1 1/2 feet tall, glandular-hairy.
Leaves: 2, basal, broadly elliptic, up to 10 inches long, up to 6 inches wide, glandular-hairy, strongly veiny.
Flowers: Borne singly at the tip of the leafless stem, up to 3 inches long.
Sepals: 3, united, unlike, the upper one narrowly lanceolate, greenish brown to greenish purple, up to 2 inches long, up to 3/4 inch wide, the lateral two up to 1 3/4 inches long, up to 1 1/4 inches wide, greenish brown to greenish purple.
Petals: 3, unequal, the 2 lateral ones lanceolate, greenish brown, hairy on the inner face, scarcely twisted, up to 2 1/2 inches long, up to 3/4 inch wide; lip petal pouch-shaped, drooping, pink or rose, up to 3 inches long, with a deep cleft down the middle.
Stamens: 2.
Pistils: Ovary inferior.
Fruits: Capsule ellipsoid, up to 2 1/2 inches long.

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Return to Species List -- Group 4
Next Species -- White Lady's-slipper (Cypripedium candidum)

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URL: http://www.npwrc.usgs.gov/resource/plants/florane/species/4/cypracau.htm
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Page Last Modified: Thursday, 03-Aug-2006 11:39:25 EDT
Menlo Park, CA [caww55]