The protonema may give rise to many moss plants. X-S of caulalia shows a central cylinder, a cortex and an epidermis. Many mosses are monoecious - Male and female in same plant. Others are dioecious . Antheridia of mosses are essentially the same as in liverworts.
Archegonia differ in having a longer neck and longer stalk to the archegonium.
Following fertilization, the embryo begins to form, with the foot penetrating into the venter and even to the apex of the leafy gametophyte. As the seta elongates, the old archegonium is torn from the gametophyte and remains on the capsule as the calyptra . Sporogenous tissue forms around the columella , and spore mother cells undergo meiosis to form tetrads of haploid spores. At the top of the capsule is the cap-like operculum beneath which is a double row of triangular peristome teeth . The teeth are attached to a thick-walled annulus around the upper end of the sporangium.