Term:

Colleter
Definition:

A multicellular, simple or branched, glandlike structure found in the axils of stipules, bracteoles, bracts, and leaf blade margins that produce mucilage which may contain terpene-based resins.
Notes:

Colleters are widely distributed in approximately sixty angiosperm families (Thomas, 1991) and are especially common common in Rubiaceae and Apocynaceae. The distinction among colleters, trichomes, and stipules is often not clear but generally speaking colleters are best defined as structures that produce mucilage (Paiva, 2012). In the Apocynaceae collecters are glands located along the interpetiolar lines or in the leaf axil that are sometimes mistaken for stipules.