Plant: medium-sized to 30 cm tall. Leaves slender to 5 cm broad and usually undulate.

Flowers: large 2-50 mm long, pale green, almost white, with few wide spaces between stripes. Dorsal sepal smoothly and evenly curved throughout its length. Labellum tapered green, its upper third sharply arched forward well beyond the sinus of the lateral sepals.

Flowering: November to February.

Habitat: lowland to montane wetlands, stream edges and bogs. Waikato to Nelson.

Conservation: locally abundant but habitat often threatened; nationally critical.

Notes: often found in highly modified habitats such as under crack willow.

Key features: wetland habitat, large flower with large white areas and long smooth curve of the dorsal sepal.