FEATURES IN THE PERIPHERAL AND POSTIGENOUS FILAMENTS
|epi = epithallial cells|
Filaments are terminated by meristematic cells (i. e., vegetative or subepithallial initials) which increase the filament length and thus the thallus growth.
Epithallial cells are mostly uncalcified cells forming the thallus surface (epithallium); epithallial cells may be rounded (D) or flattened and flared (E). Cells of contiguous filaments may be connected by cell fusions. Trichocytes are hair-producing large cells.