A member of the day lily family Hermerocallidaceae, flax is capable of surviving on clifftops and bone-dry cuttings as well as in swamps.  Leaves are 1 – 3 m long.

Flax played an important role in traditional Maori life. It was used to make clothing, food baskets, mats and fish traps. Fibre was extracted from the leaves by first scraping them with a mussel shell. It was then washed, dried and bleached in the sun. The fibre was rolled into a double thread for weaving. 

Flower stalks were made into rafts and nectar from the flowers sweetened fern root meal. The orange gum from the base of the plant was administered as an antiseptic and used to stop bleeding.

When flowering flax provides nectar for honeyeaters. The seeds are eaten by kakariki and the bushy clumps provide shelter and nesting sites for penguins.  Flowering is from November to January, with seeds from February to March.