A endothelial cell of a lymphatic vessel. The border of the oak leaf-shaped endothelial cell of initial lymphatics are joined by specialized buttons. The discontinuous feature of buttons distinguishes them from zippers in collecting lymphatics, but both types of junctions are composed of proteins typical of adherens junctions and tight junctions found in the endothelium of blood vessels. Buttons seal the sides of flaps of the oak leaf-shaped endothelial cell, leaving open the tips of flaps as routes for fluid entry without disassembly and reformation of intercellular junctions. [ http://www.ncbi.nlm.nih.gov/pubmed/17846148 GOC:tfm ]