EUROPE AND NORTH AMERICA. 23 



results, whose outer coat consists of two cell layers, beneath which 



lies another series of three strata, the central of these consisting of 



rather larger cells become parent cells of spores, while the stratum 



on each side of it represents the inner and outer wall of the future 



spore sac. The mother cells of the spores are globular, and their 



contents divide transversely by cross walls into four pyramidal 



spores ; or each of these again divides into four to form the rarer 



microspores. 



The perfect Fruit. 



The capsule is normally placed in the capitulum, but it fre- 

 quently happens that a rapid extension of the internodes takes 

 place, and thus the fruits are left behind at various heights on the 

 stem ; this usually happens by some change in the local conditions, 

 as, for instance, a sudden submergence of the plants by a wet 

 season. 



As the fruit receptacle elongates to a pseudopodium it draws 

 apart also the perichaetial bracts, which are larger than the leaves 

 and surround it at the base, and to a greater or less extent above 

 it, according to its rapidity or slowness of growth. 



The Sphagna were by all the early bryologists described as 

 being without a vaginula, and Bridel formed them into a separate 

 section termed Evaginulati, but Professor Schimper indicates as 

 the vaginula the turbinate swelling below the capsule, which 

 is the dilated apex of the receptacle. In the Acta Soc. Scient. 

 Fennicce, x. p. 264, Professor Lindberg points out that the 

 pseudopodium which carries the fruit differs from a branch in 

 having the same number of cuticular cell strata as the stem, 

 though not so well developed, and that this organ is truly nothing 

 else but an elongated vaginula. Up to the maturity of the capsule 

 it remains enclosed in the perichsetium, the receptacle then elon- 

 gates and elevates the capsule, which is inserted by its bulbiform 

 pedicel in the expanded apex. 



The calyptra is the continuation upward of the outer cell layer 

 of the vaginula and fruit receptacle, and is very thin and colourless ; 

 it encloses the young capsule like a sac closely stretched over it, 

 and does not separate in any determinate way as in mosses, but is 

 ruptured irregularly by the enlargement of the capsule and splits 

 into shreds, a portion being generally left attached to the base of 

 the capsule. 



The capsule is very uniform in all the species, being almost 



