Erect or straggling herb, 0.6-2 m, much-branched. Stem and branches indistinctly quadrangular, striate or sulcate, subglabrous to moderately (rarely more densely) hairy, the nodes frequently much shrunken when dry. Leaves elliptic-oblong to broadly oval, rarely narrowly lanceolate, shortly or longly acuminate, gradually or more abruptly narrowed below, (4.5-) 9-22 (-28) x (1.2-) 2.5-8.5 (-10) cm, usually thinly hairy (or moderately so along the lower surface of the veins), rarely densely appressed-hairy on the lower surface (not in Pakistan); petioles of main stem leaves 3-20 (-30) mm, shortening above and below. Inflorescences at first dense, finally lax and elongating to as much as 20 cm but commonly about half this length, peduncles 1-4 (-6) cm. Bracts narrowly lanceolate, brownish-membranous, 3-5 mm, glab¬rous. Bracteoles 3.5-5.5 mm, the basal wings c.0.5-1.5 mm, almost or quite free from the commonly outwardly curving spine or (as in Pakistan) variably adnate to it. Perianth segments 5, 4-7 mm, the outer longest, all narrowly lanceolate, very acute, with a distinct midrib and 2 obscure or obvious lateral nerves, narrowly pale-margined. Stamens 5, the filaments 2-3 mm, alternating with subquadrate pseudo-staminodes which are typically simple and shortly dentate or sub-entire, more rarely (and not in Pakistan) with a much shorter rudimentary tooth- or crest-like, shortly toothed dorsal scale. Style slender, 1-2 mm. Capsule 2-3 mm. Seed filling the capsule, cylindrical smooth.
Type: Mt. Burangrong, Java, Blume 897. 294-84 (L, lectotype).
Distribution: Asia from India and Ceylon eastwards to China, Japan, Indonesia and the Solomon Islands; also in east and west tropical Africa. In Pakistan (as in Africa, India and Malaysia), a plant of more “native” habitats (woodland rides, forest margins and clearings etc.) in the north, ascending to at least 2400 m and perhaps not occurring below 1200 m altitude.
In Pakistan Achyranthes bidentata is distinguishable from Achyranthes aspera by its simple pseudostaminodes and much less hairy leaves and stem. The basal wings of the bracteoles are adnate to the central spine (as in the western Himalayas of India), and not free from them in the manner of Achyranthes bidentata as it occurs east-wards from Ceylon, the Eastern Ghats and the eastern Himalayas.