The photo at right shows Listera cordata from the Timberline Trail around Mt. Hood, west of Cloud Cap, Mt. Hood Wilderness Area.........late August 1989.
Heart-leaved twayblade is a perennial with stems 6-20 cm tall, the stems either glabrous throughout, or perhaps glandular-pubescent above the leaves. It consists of a single stem, with a pair of clasping leaves opposite of each other at mid stalk. The leaves are 1-4 cm in lengthand about as wide, and they are broadly heart-shaped, with parallel leaf venation. They are opposite of each other on the stem.
The flowers are pale green to purplish-brown in color, with the lip divided into 2 linear lobes with a pair of horn-like teeth at the base. The lip is 4-11 mm long and hairless and lacks ciliate margins. The sepals and petals are 2.5-4.5 mm long. The 5 to 16 flowers form an elongated, open, terminal raceme.
Heart-leaved twayblade is a plant of damp, mossy places, often found along streams or in bogs in moist coniferous forests. It may on occasion be found in dry forested areas or on open slopes.
Heart-leaved twayblade is found from Alaska to Greenland. On the east coast, it may be found as far south as North Carolina, in the Midwest, it is found as far south as Minnesota and Michigan, and in the west as far south as New Mexico and California. It is found in the mountainous areas of both Oregon and Washington.