Trachyandra is placed in the family Xanthorrhoeaceae, subfamily Asphodeloideae. The name Trachyandra is derived from the Greek words, trachy, meaning rough, and andro, meaning male, and refers to the scabrid (hairy) filaments of the stamens. There are ± 55 species that mainly occur in southern Africa, particularly the Western Cape, but some species extend into tropical Africa as far as Somalia. They are mostly perennial bulbous plants.

Trachyandra revoluta is a South African indigenous species from the Eastern Cape, Northern Cape and Western Cape Provinces. It is commonly known as Hotnotskool, Water Grass, Watergras, Waterknolle and Watertoue and was previously known as Anthericum elongatum, Anthericum revolutum, Dilanthes revolutum, Phalangium revolutum and Trachyandra elongata. It grows to 50cm tall and is usually found along the coast in damp sand. During spring it bears white flowers with brown keels.