Arthrodontous capsule of Dicranella varia
The Bryopsida constitute the largest class of mosses, containing 95% of all moss species. Plants are living Organisms belonging to the kingdom Plantae. Mosses are small soft Plants that are typically 1–10  cm (0 The Diphysciaceae is a family of Mosses Members of this family are small perennial plants The Funariidae are a widespread group of Mosses in class Bryopsida. The Dicranidae are a widespread group of Mosses in class Bryopsida, with many species of dry or disturbed areas Bryidae is an important subclass of Bryopsida. It is common throughout the whole world A class is the Taxonomic rank in the Biological classification of organisms in Biology below phylum and above order. Mosses are small soft Plants that are typically 1–10  cm (0 In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. It consists of approximately 9,500 species, common throughout the whole world.
The group is distinguished by having spore capsules with teeth that are arthrodontous; the teeth are separate from each other and jointed at the base where they attach to the opening of the capsule. A sporangium (pl sporangia) is a Plant or fungal structure producing and containing Spores Sporangia occur in angiosperms,  These teeth are exposed when the covering operculum falls off. In Botany, operculum may be used to describe any of the following A flap of the sporangium of a moss, covering the peristome (appendages surrounding In other groups of mosses, the capsule is either nematodontous with an attached operculum, or else splits open without operculum or teeth.
Among the Bryopsida, the structure of the capsule (sporangium) and its pattern of development is very useful both for classifying and for identifying moss families. A sporangium (pl sporangia) is a Plant or fungal structure producing and containing Spores Sporangia occur in angiosperms, Most Bryopsida produce a capsule with a lid (the operculum) which falls off when the spores inside are mature and thus ready to be dispersed. In Botany, operculum may be used to describe any of the following A flap of the sporangium of a moss, covering the peristome (appendages surrounding In Biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions The opening thus revealed is called the stoma (meaning "mouth") and is surrounded by one or two peristomes. A peristome is a ring of triangular "teeth" formed from the remnants of specially thickened cell walls. The word peristome is derived from the Greek peri, meaning 'around' or 'about' and stoma, 'mouth' A cell wall is a tough flexible and sometimes fairly rigid layer surrounding a cell, located external to the Cell membrane, which provides the cell with structural There are usually 16 such teeth in a single peristome, and in the Bryopsida the teeth are separate from each other and able to both fold in to cover the stoma as well as fold back to open the stoma. This articulation of the teeth is termed arthrodontous.
There are two basic arthrodontous peristome types.  The first is termed haplolepidous and consists of a single circle of 16 peristome teeth. The second type is the diplolepidous peristome fround in subclass Bryidae. Bryidae is an important subclass of Bryopsida. It is common throughout the whole world In this type, there are two rings of peristome teeth—an inner endostome (short for endoperistome) and an exostome. The endostome is a more delicate membrane, and its teeth are aligned between the teeth of the exostome. There are a few mosses in the Bryopsida that have no peristome in their capsules. These mosses still undergo the same cell division patterns in capsule development, but the teeth do not fully develop.