| tapetum [tǝ`pēd·ǝm] ANATOMY 1. A reflecting layer in the choroid coat behind the neural retina, chiefly in the eyes of nocturnal mammals. 2. A tract of nerve fibers forming part of the roof of each lateral ventricle in the vertebrate brain. BOTANY A layer of nutritive cells surrounding the spore mother cells in the sporangium in higher plants; it is broken down to provide nourishment for developing spores. |