136 MUSCINE^E 



closely to the ground or to some other substratum ; and even in the 

 foliose forms there is a well-marked tendency to the differentiation of an. 

 upper or dorsal and an under or ventral surface. The non-sexual 

 generation or sporogone remains surrounded by the calypter until the 

 spores are ripe ; the calypter is usually at length ruptured at the apex, 

 and remains at the base of the sporogone as an open sheath, while the 

 sporange projects above its apex to allow the escape of the spores. The 

 mother-cells of the spores are either developed from the whole of the 

 archespore, or, in most families, some of the cells develop into elaters ; 

 there is no columel. 



LITERATURE. 



Hofmeister On the Germination, Development, and Fructification of the Higher 



Cryptogamia, Ray. Soc., 1862. 

 Leclerc du Sablon., Ann. Sc. Nat, 1885, p. 126; and Bull. Soc. Bot. France, 



1885, pp. 30 and 187. 

 Goebel Die Muscineen, in Schenk's Handbuch der Botanik, vol. ii., 1882. 



Class VII. Musci. 



The germinating spore of Mosses gives rise to a prothallium which is 

 always in the typical families of a filamentous conferva-like character, 

 and is hence known as the protoneme. On this is produced the leafy 

 plant with differentiated stem and leaves by lateral budding. These 

 together, therefore, constitute the sexual generation or oophyte, which 

 terminates in the production of the sexual organs. From the fertilised 

 oosphere proceeds the sporogone^ which comprises in itself the non-sexual 

 generation or sporophyte. 



The protoneme first originates, in typical mosses (Bryacese), as a 

 tubular bulging of the endospore or inner coat of the spore, divisions 

 taking place in it in the transverse direction only. It has an unlimited 

 power of apical growth, and often branches copiously, forming a dense 

 felt of considerable size above or below the surface of the soil, in the 

 former case densely filled with chlorophyll. The protoneme usually 

 disappears altogether after the appearance on it of the leafy plant ; but 

 in some cases, especially in the Phascacese, it remains vigorous even 

 .after the formation of the sporogone. In the Sphagnaceae the proto- 

 neme consists of a flat plate of cells ; while in the Andreaeaceae cell- 

 division begins to take place within the spore, the resulting prothallium 

 consisting of a small cellular tissue. The buds which develop into the 



