MUSCI 151 



The calypter is elevated, as in the Bryaceae, on the summit of the ripe 

 sporogone in the form of a cap ; there is a short seta buried in the vagine, 

 and the whole sporogone is elevated on a stalk or pseudopode, as in the 

 Sphagnaceae. At the base of 

 the sporange is an enlarged 

 apophyse. The structure of 

 the sporange differs from that of 

 the Bryaceae in the columel not 

 penetrating the archespore, and 

 in the absence of a cavity be- 

 tween the spore-sac and the 

 wail of the sporange. The con- 

 tents of the spore divide, while 

 still within the exospore, into 

 four or more cells. As in Sphag- 

 num, the oosphere is always 

 enveloped in a hyaline mass of 

 mucilage in which the anthero- 

 zoids imbed themselves. 



The Andreaeaceae are also 

 caespitose in their habit, and are 

 natives of cold or mountainous 

 regions. 



FIG. 124. A. alpestris 



Schmp. ; dehiscent spo- 

 range and apophyse 

 (magnified). 



FIG. 123. Andrecea 

 alpcstris Schmp. 

 (* 5)- 



LITERATURE. 



Kiihn Entwickelungsgeschichte der Andreseaceen, 1870. 



\Valdner-Bot. Zeit., 1879, p. 595; and Entwick. d. Sporogone v. Andresea, 1887. 



ORDER 4. SPHAGNACEAE. 



The bog-mosses form a large portion of the vegetation of bogs and 

 swamps, and are characterised by the spongy structure of the whole 

 plant, the light yellowish green colour of the leaves, and the bright red 

 globular spore-capsules. The protoneme is much less developed than 

 in typical mosses ; and when the spore germinates on dry ground a 

 flat prothallinm intervenes between it and the leafy stem. The stem 

 branches abundantly, giving a caespitose appearance to the whole plant ; 

 and innovations, produced below the apex after the ripening of the 

 fructification, become detached by the decay of the lower part of the 

 stem, and carry on an independent existence. The leaves are lanceolate 

 and apiculate, usually arranged in a |- phyllotaxis, larger than in other 

 mosses, and of a peculiar structure of their own. As the leaf develops, 



