lig·ule 
(lĭgyl)
(lĭgyl)n.
A straplike structure, such as the long flattened lobe of the corolla of a ray flower or a membranous or hairy appendage between the sheath and blade of a grass leaf.
[Latin ligula, diminutive of lingua, tongue; see dghū- in the Appendix of Indo-European roots.]