Western twayblade is a perennial to 30 cm tall. It consists of of a single stem with two opposite, oval to broadly elliptical leaves with parallel leaf venation. The leaves are found near mid-stem. The tips of the leaves are pointed and the bases are clasping. The stem above the leaves is generally very hairy.
The flowers are pale green to yellowish in color, with a rounded lip having a pair of horn-like teeth at the base. The 5 to 25 flowers form a terminal raceme.
Western twayblade is found in moist, coniferous forests, along streambanks, and in wet meadows. It is found from low elevations to subalpine habitats.
Western twayblade is found from southern Alaska east to the western slopes of the Canadian Rockies. From there, the distribution is southward through Idaho, Montana, the Pacific Northwest, and hence to northwestern California.
In the Columbia River Gorge, it may be found east of Multnomah Falls to about Dog Mt.. Within that range, it may be found between the elevations of 2800'-4000'.
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