Oplismenus thwaitesii is a flowering plant that is endemic to India.

The species also has 3–4 unilateral racemes which are located along the central axis, and are 1–2 centimetres (0.39–0.79 in) long.

Just like the lower glume, it is pubescent on the bottom but has an obtuse apex which can also be mucronate or muticous as well.

The lower sterile floret of the lemma is ovate and is 1 length of a spikelet which is also emarginate, membranous and mucronate.

The fertile lemma is coriaceous, keelless, oblong, shiny and is 2–2.5 millimetres (0.079–0.098 in) long with involute margins and acute apex.