Peristome teeth

Peristome teeth thin, developed in the amphithecium and derived from the cell walls of a single layer of cells, always transversely barred sometimes entirely wanting. 

Peristome teeth solid, rarely absent, developed from two or more tissue layers of the sporangium, not transversely barred or... 

Ingold, C. T. (1959) Peristome teeth and spore discharge in mosses. Transactions of the Botanical Society of Edinburgh, 38 76-88. 

Peristome double or sometimes wanting plates of the outer side of the teeth mostly in two rows by a zigzag line, the inner side of the teeth consisting of a single row of plates endostome thin and membranous, sometimes lacking. 

Endostome processes opposite the teeth of the exostome, either free or united with them, but the peristome sometimes entirely wanting hypophysis sometimes highly developed acrocarpous mosses.Order Splachnales (Funariales)... 

Peristome In mosses, the fringe of teeth surrounding the orifice of the capsule. 

The exostome is formed from the common periclinal cell wall pair between the inner wall of the OPL and the outer wall of the PPL. The endostome is formed from the common periclinal cell wall pair between the inner wall of the PPL and the outer wall of the IPL (Figure 12.1). Autolysis of the anticlinal walls of the cells between the exostome and the endostome separates the two rings of the diplolepidous peristome, while autolysis of the periclinal walls between adjacent teeth separates the structures within each ring of the peristome. In reduced peristomes this autolysis may be incomplete, leaving adjacent structures partially attached. 

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