The opposite, erect leaves of Chasmatophyllum musculinum are rough-surfaced, particularly in the dry seasons. The leaf bases sheathe the stem.

There is usually a whitish tooth protruding from the back of the keeled leaf. Up to four soft, whitish teeth may occur on each leaf margin, or it may be untoothed.

The generic name, Chasmatophyllum, is derived from the Greek words chasma meaning gaping mouth and phyllon meaning leaf, referring to the spreading habit of the leaf tips. The tiny tubercular leaf surface protuberances are variable, here showing translucence (Frandsen, 2017; Smith, et al, 1998; iSpot).