[The Orchid Family East of the Cascade Mts.]
Twayblades East of the Cascade Mts.

The Genus Listera

Heart-leaved Twayblade: Listera cordata
1. Northern Twayblade: Listera borealis - Lower lip narrow, deeply cleft into 2 lobes. Leaves elliptic in shape. Lip is finely haired with ciliate margins.

2. Western Twayblade: Listera caurina - Lower lip widened at the tip, the tip rounded or slightly notched but not deeply cleft. Lip not ciliate on the margin. Ovary and capsule not glandular-hairy.

3. Broad-lip Twayblade: Listera convallarioides - Lower lip widened at the tip, the tip rounded or slightly notched but not deeply cleft. Lip ciliate on the margin. Ovary and capsule glandular-hairy.

4. Heart-leaved Twayblade: Listera cordata - Lower lip narrow, deeply cleft into 2 lobes. Leaves broad, mostly ovately-cordate. Lip is hairless.

Paul Slichter