The grasses are very diverse in habit and structure, but are characterised by elongate, parallel-veined leaves with sheathing bases and a distinctive inflorescence structure . The leaves of almost all the species have ligules (a membranous rim or line of thin hairs across the inner surface of the leaf where the leaf blade joins the sheathing base).

Identifying grasses is difficult and depends on very careful determination of the type of inflorescence and the structure and composition of the spikelets.

The key to this family is still under development.