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Western Wetland Flora

Field Office Guide to Plant Species

Small Yellow Lady's-slipper
Cypripedium calceolus L.

JPG -- Species Photo JPG -- Distribution Map

Family: Orchid (Orchidaceae)
Flowering: April-June
Field Marks: The lady's-slipper orchids are distinguished by the large lip petal that resembles a slipper. This species has a yellow lip and 3-6 leaves on the stem.
Habitat: Along streams, in rich woods, in swamps.
Habit: Perennial herb with short rhizomes and fibrous roots.
Stems: Upright, up to 1 1/2 feet tall, glandular-hairy.
Leaves: Alternate, simple, 3-6 on each stem, broadly lanceolate to elliptic, up to 8 inches long, up to 4 inches wide, pointed at the tip, tapering to the sessile base, glandular-hairy, strongly veined.
Flowers: Usually 1 at the tip of the stem, sometimes 2 or more, each on a stalk at least 1/2 inch long, subtended by a pointed bract 2-5 inches long.
Sepals: 3, yellow, greenish, or purple-brown, one of them narrowly ovate, pointed, and wavy along the edges, the other 2 united and situated below the lip petal.
Petals: 3, 2 of them yellow, greenish, or purple-brown and wavy-edged, up to 4 inches long and up to 1/2 inch wide, the other one (the lip) forming a yellow slipper up to 2 1/2 inches long.
Stamens: 2.
Pistils: Ovary inferior, ribbed.
Fruits: Capsules ellipsoid, up to 2 inches long, up to 1/2 inch wide.
Notes: Throughout its range there is much variation in size of the yellow lip and color of the other petals and sepals.

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