SUMMARY1.The apothecia ofThelotrema interpositumarise from a group of ascogonial coils, each of which is provided with a trichogyne. This initial is similar to that which has been described in many lichen groups.2.Spermatium-like bodies have been found attached to the“paraphyses”of some of the apothecia. These are unusual in their nature and place of occurrence, but they seem best interpreted either as asexual spores or (more probably) as spermatia. There is some evidence that they may fuse with the trichogyne.3.Asci are formed from ascogenous hyphae, apparently through typical croziers. The asci first grow in length and the sheathing membrane may not appear until a later stage. After division of the definitive nucleus, one of the resulting nuclei is delimited in a small unit of the epiplasm by a very distinct membrane and this spore initial grows to fill the ascus. Most asci contain some puzzling chromatin-like material.