The Genus Listera
Northwest Twayblade, Northwestern Twayblade, Western Twayblade: Listera caurina (Synonyms: Listera banksiana, Listera retusa, Neottia caurina, Ophrys caurina) - Lower lip short, ovate to pear-shaped and rounded to occasionally very shallowly notched at the tip.
Broadleaf Twayblade, Broad-lip Twayblade, Broadlipped Twayblade, Broad-lipped Twayblade: Listera convallarioides (Synonyms: Bifolium convallarioides, Diphryllum convallarioides, Epipactis convallarioides, Listera eschscholziana, Ophrys convallarioides) - Lower lip long, narrowly triangular in shape, tapering gradually tapering to the base, which abruptly narrows to its attachment at the base of the flower. Tip of lower lip shallowly notched into 2 ciliate lobes.
Heartleaf Twayblade, Heart-leaf Twayblade, Heart-leaved Twayblade: Listera cordata var. nephrophylla (Synonyms: Bifolium cordatum, Diphryllum cordatum, Distomaea dordata, Listera cordata ssp. nephrophylla, Listera cordata var. cordata, Listera nephrophylla, Neottia cordata, Neottia nephrophylla, Ophrys cordata, Pollinirhiza cordata) - Lower lip cleft about half its length into 2 narrow, divergent lobes.