The leaf

A grass leaf has a sheath, which wraps around the stem, and a blade. At the place the two meet (the collar) there may be a ligule on the adaxial surface (a flap of tissue that sticks up and continues to hug the stem) and/or auricles (two little lobes or appendages stick out or forward at the base of the blade).

Shapes, sizes, and presence or absence of ligules and auricles is often important in identifying grasses. A concise glossary page that shows a wide variety of ligules and auricles is available on the web through this link

Check your understanding:

 The collar regions of two grass leaves are shown below. These are from different species.