This sedge grows 40 centimeters to 1.2 meters tall with leathery leaves as long as the stem or longer.

The flower cluster atop the stem is umbrella-shaped and up to 15 centimeters long by 25 wide.

[3] Today, this plant grows on Maui, Kauai, and Laysan; it has recently been extirpated from Oahu and the island of Hawaii.

[2] The most recent surveys found about 30 individual plants on Maui and four populations on Kauai; these represent the subspecies pennatiformis.

The habitat is a type of coastal forest dominated by hala (Pandanus tectorius).