Pronunciation: (en"dō-thē'shē-um, -sē-um),[key] —n., —pl.-ci•aPronunciation: (-shē-u, -sē-u).[key]Bot. 1. the lining of the cavity of an anther.
2. (in mosses) the central mass of cells in the rudimentary capsule, from which the archespore is generally developed.
3. (in bryophytes) the central mass of cells in the capsule, including the spores and columella.