This article surveys the structural, functional and phylogenetic significance of colleters in different dicotyledonous families. Colleters are multicellular secretory structures attached to the stipule, petiole, lamina, bract, bracteole, calyx and corolla. Colleters are grouped into standard (S), dendroid (D) and brush-like (B) types on the basis of their morphology and structure. D and B-type colleters occur in certain members of Rubiaceae that also have bacterial leaf nodules. Besides the normal structure, epithelial hairs, thin-walled subepidermal cells, laticifers and vasculature are present in many colleters of Apocynaceae. It is probable that the colleter functions to protect the developing meristem by secreting a viscous fluid. Exudate of D-type colleters are mucilaginous, providing the substrate necessary for the nutrition of endophytic bacteria.

No abstract

1989. Anatomy and histochemistry of colleters in Roupelia grata (Apocynaceae). -Nord. J. Bot. 8: 493496. Copenhagen. ISSN 0107-055X. The colleters of Roupelia grata are present on the petiole of the leaf, bract, bracteole and calyx. A mature colleter has a distinct head and a stalk. The parenchymatous central core is surrounded by epithelial cells. The senescence of the colleter occurs at its apex first and then proceeds towards the base.

No abstract

No abstract