Achyranthes humilis is a shrub with erect to decumbent stems measuring 1–5 meters long. It is openly branched and sparsely pubescent with short, appressed hairs. The leaves are simple and opposite, with blades that are ovate to oblong, 3–9 cm long, and 2–5 cm wide, with juvenile or young flowering plants having narrower leaves than mature plants. The leaf apex is obtuse to rounded, and the base is cuneate to truncate. The surfaces are moderately pubescent with short appressed hairs, becoming glabrate with age. The margins are entire, and the leaves are pinnately veined. The petioles are 4–8 mm long, and stipules are absent. The flowers are arranged in slender spikes 3–14 cm long and about 4 mm or less in diameter, with peduncles 0.5–1.5 cm long. The flowers are bisexual (perfect), broadly ovoid, and actinomorphic (radially symmetric), each subtended by a persistent bract and two bracteoles. The calyx consists of 4 equal, ovate sepals about 3 mm long, pubescent with short, appressed to spreading hairs. The sepals are subtended by a broad ovate, scarious bract about 1 mm long and 1.5–2 mm wide, which is persistent on the rachis. The bracteoles are cordate to ovate, keeled, about 1 mm long, and deciduous with the calyx and fruit. The corolla (petals) is absent. There are four stamens, connate at the base, with dithecal anthers. The ovary is superior, 2–3(4)-carpellate, with the carpels connate to form a compound, 1-celled ovary. Ovule placentation is basal, free-central, or rarely apical. There is one style, often lobed. The fruit is about 2 mm long and enclosed by the calyx, with one seed per fruit. The seed surface is usually lustrous, and the endosperm is essentially absent. It is found in open, remnant dry forests, sometimes on cliff faces, gulches, or steep slopes between 300-700 meters.