Gossypium tomentosum is a member of the Mallow or Hibiscus family (Malvaceae). Worldwide, there are about 40 species in the genus Gossypium. Ma`o is classified as a New World cotton and is the only member of that group not cultivated. It is unfortunate that some consider Ma`o as a "weed" when it is certainly not a common species in many natural areas in the Hawaiian Islands.
The generic name Gossypium is derived from the Greek name for cotton, gossypion.
The specific epithet tomentosum from the Latin tomentosus or tomentose, meaning "covered with tangled or matted, woolly hairs."
The name Ma`o comes from the Hawaiian word ʻōmaʻo for green and shares the same name as the native Hawaiian thrush, ʻōmaʻo (Myadestes obscurus) which has a greenish cast to its feathers.
The light green/silvery leaves are 3- to 5-lobed. They are from 1 to almost 4 inches wide and are wider than they are long. Ma`o blooms from late summer through winter. Brown capsules containing light brown fuzzy seeds follow the blooming period.
Ma`o can be found growing in coastal plains to dry forests primarily on the leeward sides of all major islands except Hawai`i island, and apparently no longer naturally found on Kaua`i.