Gossypium tomentosum

Gossypium tomentosum, commonly known as mao, huluhulu or Hawaiian cotton, is a species of cotton plant that is endemic to the Hawaiian Islands. It inhabits low shrublands at elevations from sea level to 120 m. Mao is a shrub that reaches a height of 1.5 - 5 ft and a diameter of 5 - 10 ft. The seed hairs (lint) are short and reddish brown, unsuitable for spinning or twisting into thread.

Genetic studies indicate that Hawaiian cotton is related to American species of Gossypium, with its closest relative Gossypium hirsutum. Its ancestor may have come to the islands from the Americas as a seed on the wind or in the droppings of a bird, or as part of floating debris.

Native Hawaiians use mao flowers to make a yellow dye.