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Western Wetland Flora

Field Office Guide to Plant Species

Broad-leaf Twayblade
Listera convallarioides (Swartz) Nutt. ex Elliott

JPG -- Species Photo JPG -- Distribution Map

Family: Orchid (Orchidaceae)
Flowering: June-July
Field Marks: This species is recognized by the single pair of round leaves on the stem, by the yellow-green flowers in an uncrowded raceme, and by the narrowly ellipsoid capsule.
Habitat: Along streams, damp woods at the upper elevation of mountains.
Habit: Perennial herb with a short rhizome and fibrous roots.
Stems: Upright, unbranched, up to 10 inches tall, smooth below the pair of leaves, glandular-hairy above them.
Leaves: Opposite, simple, in a single pair about 1/2 way up the stem, nearly round, up to 2 1/2 inches long, nearly as wide, rounded or with a short point at the tip, rounded at the sessile base, smooth.
Flowers: 5-15 in an uninterrupted terminal raceme, each flower yellow-green, subtended by a bract 1/8-1/4 inch long; flower stalks slender, up to 1/3 inch long.
Sepals: 3, free from each other, yellow-green, linear to broadly lanceolate, pointed at the tip, up to 1/4 inch long, curved backward.
Petals: 3,2 of them resembling the sepals, yellow-green, linear to broadly lanceolate, pointed at the tip, up to 1/4 inch long, curved backward; lip petal 1/3-1/2 inch long, 1/4-1/3 inch wide, yellow-green, notched at the tip, abruptly tapering
Stamens: 10, associated with the pistil to form a column.
Pistils: Ovary inferior, the pistil associated with the stamen to form a column.
Fruits: Capsules narrowly ellipsoid, up to 1/3 inch long, smooth.

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Page Last Modified: Saturday, 02-Feb-2013 06:25:14 EST
Menlo Park, CA [caww55]