When a male bud is developed, the antheridia are found to be globular, ovoid, or elongated hyaline bodies, set in a cluster of hairs and paraphyses, or sterile cellular filaments. Fig. 48 represents the antheridia of Polytrichum commune, with the paraphyses and hairs, from the microscopic observations of Dr. Carpenter. The central antheridium is discharging its spermatozoids; the one on the right is empty, that on the left immature. [Illustration: Fig. 47. A, plant of Funaria hygrometrica:—_f_, leaves; _u_, urns or capsules; S, seta or foot-stalk; _o_, operculum; _c_, calyptra. B, sporangia of Encalypta vulgaris:—_u_, urns; _o_, opercula; _c_, calyptra; _p_, peristome; _s_, seta.] The antheridia are filled with a mass of mucilage containing a multitude of cells, in each of which there is a spiral filament furnished with cilia, as in fig. 49. As soon as the filaments are mature, the cells open; the mobile filaments, or spermatozoids, are free, and come out through a pore in the antheridia, in multitudes like pollen out of an anther. While the antheridia are in process of formation, the female buds expand and exhibit flask-shaped archegonia, similar to that in fig. 45, seated in a rosette of leaves. When this archegonium is fertilized by the spermatozoids, its internal germ cell is developed by cell division into a conical body elevated upon a stalk; and this at length tears across the walls of the flask-shaped archegonium by a circular fissure, carrying the higher part upwards as a calyptra or hood (fig. 47 _c_) upon its summit, and leaving the lower part to form a kind of collar round the base of the stalk. [Illustration: Fig. 48. Polytrichum commune:—group of antheridia mixed with hairs and sterile filaments (paraphyses), the central one discharging its contents.] [Illustration: Fig. 49. Polytrichum commune:—B, cellular contents of an antheridium previously to the development of the spermatozoids; C, the same, showing the first appearance of the spermatozoids; D, the same, mature and discharging the spermatozoids.] The urn-shaped organ or sporangium has a double wall, and in its centre a fusiform or deeply winged columella. Between these two there is a tissue of a most delicate texture, divided into spherical cells, each of which usually produces four unripe spores, which get an exterior coat when fertilised, and then it is that the stalk lengthens, and the flask-shaped archegonium is torn across.