Here you can see both a fuzzy lingual (right) and a smooth lingual (right).
The Ligule is a membrane located on the inner side of the leaf where the leaf meets the stalk of a grass or sedge. Pull back a grass leaf and see if you can find the ligule! The ligule is fun to uncover and noticing what they look like, for example fuzzy, smooth, thin or wide can help you identify the grass!