The Microscope. 135 



half-inch objective, the flask-shaped archegones will be seen to 

 good advantage, although a higher power will be necessary to 

 show the finer details of structure. The male flowers will be 

 found close by, as this moss is monoecious; they are more 

 rosette-like in form. By treating one of these in the same way, 

 we shall find the antherids with very little trouble. They will 

 be seen to be club-shaped bodies supported on short pedicels, 

 and among them will be found numbers of the very peculiar 

 paraphyses of this genus resembling jointed rods or hairs, each 

 with a ball on its upper end. If the antherids are at the 

 proper stage of development, we shall also see the antherozoids, 

 though a much higher power, such as ^ or tV immersion, will be 

 needed to show their structure clearly. Their motion will attract 

 the eye at once. 



The presence of water is necessary to the act of fertilization. 

 When the moss is wet with dew or rain the antherozoids move 

 freely through the water by means of their cilia, and some of 

 them find their way down the open channels of the archegonia and 

 unite with the germ-cells or oospheres. "As a result of this union, 

 the germ-cell surrounds itself with a wall of cellulose, and soon 

 undergoes division in various directions, giving rise to a many- 

 celled mass, the young sporogonium. Usually the young sporo- 

 gone rapidly elongates, and soon ruptures the archegone trans- 

 versely, carrying the upper portion up with it in its growth (it 

 becomes the calyptra of the new capsule), while the lower por- 

 tion is termed the vagine or sheath. The lower end of the 

 young sporogonium penetrates some distance into the tissues of 

 the stem, the central portion becomes the slender pedicel or 

 seta, while the upper end develops into a spore-case called the 

 capsule or theca. " The spore-case differs much in its structure 

 in the diff'erent orders, but in all certain internal cells become 

 spore mother-cells, which divide into four daughter-cells, the 

 spores. 



In the great majority of mosses, including the Bryacete and 

 Sphagnaceae, the capsule is furnished with a lid, or operculum, 

 which falls off" at maturity, permitting the spores to escape. In 

 the Andrseaceae the capsule opens by four longitudinal slits. In 

 the small order Phascaceaj the spores are set free only by its ir- 

 regular rupture or decay. 



The falling off of the operculum discloses the peristome, a 



