Gossypium tomentosum, commonly known as Hawaiian cotton, is a species of cotton shrub that typically grows to heights between 0.5 and 1.5 meters. The plant is characterized by its soft, white tomentose covering. Its leaves are simple and alternate, often wider than long, ranging from 3 to 12 cm in width. These leaves are usually 3-lobed but can sometimes be 5-lobed up to about the middle, with the lobes being ovate and either acute or subacuminate at the tips. Both surfaces of the leaves are tomentose, and the margins are lobed but otherwise entire. Notably, the midvein on the lower surface lacks a basal gland, or it is obscure. The plant features subulate stipules that are 0.5 to 0.8 cm long and caducous. The flowers are solitary, or a few may be found in short cymes, with involucral bracts that are ovate, 15–25 mm long, dentate, and have 5–9(–12) acute teeth. The flowers are bisexual (perfect), with an erosely truncate calyx measuring 7–9 mm long and connate sepals. The corolla, which is actinomorphic to moderately zygomorphic, consists of 5 bright yellow petals (without a maroon spot) that fade to greenish, measuring 2–3.5(–4) cm in length and are campanulate to funnelform. The stamens are united into an included and antheriferous column for most of its size or only in the upper half. The fruit is a loculicidal, usually glabrous capsule that is 3-celled, coriaceous to woody, ovoid, and cuspidate, and measures 1.2–1.8 cm in length with a black-pitted surface. Each cell contains 2–4 seeds approximately 13 mm with hairs and 5 mm long without hairs, densely covered with reddish-brown lint, and turbinate in shape, with or without endosperm. It primarily occurs in arid, rocky, or clay coastal plains between 0–120 meters.