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black, this is a felted web of minute branched filaments of protonema, 

 from which young plants bud off as in other mosses; these are at 

 first globose and extremely minute. The almost invisible leaves are 

 rather to be looked upon as perichaetial bracts, and are peculiar in 

 the flagelliform prolongations of the marginal cells, which give them 

 a lacerated appearance, and long before the calyptra is cast off they 

 become brown and dead. The reason of this is explained by Zukal 

 thus: — "Their activity probably consists in the transmission of 

 moisture, and along with the adventitious radicles they first form 

 a protection to the young archegonium, and then in the act of 

 impregnation serve as a sponge, to take up fluid swarming with 

 antherozoids, and convey them to the waiting archegonia, this 

 function ended, they wither and die." 



Taking a single plant, we observe at the base a bulb-like swelling 

 covered with a close felt of proembryo filaments and minute leaves, 

 this by vertical section we find is a cup-like sheath, embracing the 

 base of the seta, the outer cells of which are large, quadrate, with 

 thick walls and colorless contents, and become the cuticle of the seta, 

 the cells internal to this layer being long and thin walled, constitute 

 the bundle of vascular cells forming the centre of the seta, while the 

 cup-like sheath is all we find to represent the parenchyma of the 

 stem. In the free seta the first two elements are more fully developed, 

 the outer cuticular cells being still further thickened into warts. 

 Where the seta joins the capsule an elegant neck is formed, through 

 the centre of which the vascular bundle is continued as the pedicel 

 of the spore sac, and then enlarges into the columella and passes 

 on to the apex of the operculum. Around the columella is the spore 

 sac composed of three cell-layers, the cavity between it and the 

 capsular wall being traversed by numerous jointed confervoid filaments. 

 A transverse section through the lid, before maturity, shows us a 

 circle of large triangular cells, the two lateral sides being equal, and 

 the shorter base turned alternately inward and outward, thus forming 

 a wavy zigzag round the central bundle of vascular cells. In course 

 of growth the short bases become entirely resorbed, while the lateral 

 sides of the triangles grow together and become thickened into a 

 membrane, and their outward angles further strengthened by a stout 

 ridge of cellulose. It thus forms an enduring, rigid, tubular, tent-like 

 endostome, the function of which is thus remarked on by Zukal : — 

 " In many mosses the peristome only serves to prevent the spores 

 passing out of the capsule in unfavorable weather; if the spores 

 require warm, dry air as a necessary condition for germination, then 

 the peristome is so adapted that in wet, rainy weather it completely 

 closes the mouth, and on the contrary, if moisture be the condition 

 needed, then in dry weather the peristome closes the mouth of the 

 capsule. The spores of many mosses are first set free by the falling 

 in pieces of the capsule by decay, and until this occurs they must be 



