Neottia convallarioides is a species of orchid known by the common names broad-lipped twayblade and broad-leaved twayblade. It was formerly placed in the genus Listera, but molecular phylogenetic studies have shown that Neottia nidus-avis, the bird's-nest orchid, evolved within the same group, and all species of Listera have been moved to Neottia.
Neottia convallarioides is native to much of Canada and in parts of the United States (Alaska, the Great Lakes Region, New England, and the mountains of the West: Rockies, Cascades, Sierra Nevada, etc.). I also reportedly occurs in St. Pierre & Miquelon and on the Komandor Islands in the Bering Sea, part of the Russian Far East.
Neottia convallarioides is a plant of cool, moist, dim habitat, such as woods and forest, as well as swamps and streambanks. It is a rhizomatous perennial herb growing erect 10 to 35 centimeters tall. It has one pair of green oval leaves each up to 7 centimeters long near the base of the stem. The inflorescence is a small raceme of green or yellow-green flowers, sometimes slightly purple-tinged. Each has usually 3 reflexed lance-shaped sepals, 2 similar petals, and one petal known as the lip, which is longer, wedge-shaped, and notched at the tip. The plant sometimes forms large colonies, creating a groundcover. It is known to hybridize with Neottia auriculata.
- "Neottia convallarioides", World Checklist of Selected Plant Families, Royal Botanic Gardens, Kew, retrieved 2012-04-04
- Stace, Clive (2010), New Flora of the British Isles (3rd ed.), Cambridge, UK: Cambridge University Press, ISBN 978-0-521-70772-5, p. 864
- "Listera", World Checklist of Selected Plant Families, Royal Botanic Gardens, Kew, retrieved 2012-04-04
- Flora of North America v 26 p 590, Broad-leaved twayblade, Listera convallarioides (Swartz) Nuttall ex Elliott, Sketch Bot. S. Carolina. 2: 494. 1823.
- Biota of North America Program, 2013 county distribution map, Neottia convallarioides
- Hoy, J. (2002). Conservation Assessment for Broad-leaved Twayblade (Listera convallarioides). USDA. White Mountain National Forest.