Heteropogon contortus is a perennial grass that grows in tufted, erect culms 40–100 cm tall, with a compressed and glabrous form, often appearing glaucous. Its roots are fibrous, supporting leaves that are simple and alternate, with blades measuring 10-30 cm long and 3-7 mm wide. The leaf surfaces are pale, bluish-green, and firm and can range from flat to slightly involute, displaying a striate and scabrous texture. The leaves have parallel veins, and the sheaths are 6-10 cm long, compressed, keeled, and either glabrous or sparsely hispid at the throat, often glaucous. The ligule is a ciliate membrane around 1 mm long. The flowers are in racemes that are solitary at the apex of the flowering culm, secund and often slightly nodding, measuring 4-7 cm long. The racemes have a slender rachis that is continuous in the lower part, bearing pairs of staminate spikelets, while the remainder disarticulates obliquely at the base of each joint, forming a sharp barbed callus below the fertile spikelet. The upper sessile spikelet is approximately 7 mm long with awns 5-12 cm long, bent, flexuous, and often tangled. The lower part is appressed pilose, becoming scabrous toward the apex. The lower sessile spikelet and the pedicellate spikelet are about 10 mm long, with the first glume being firm, asymmetrical, and papillose-hispid near the margins and the acuminate apex. The fruit is a terete caryopsis. The seeds’ embryo is about half as long as the grain and has a basal, punctiform hilum. It is found in dry, rocky cliffs, ledges, or slopes close to ocean exposure across all the main Hawaiian islands, at elevations ranging from sea level to 700 meters.