146 MUSCINE& 



Braithwaite The British Moss-Flora, 1880-1887. 



L'Abbe Hy Bull. Soc. Bot. France, 1880, p. 106 ; Ann. Sc. Nat., xviii., 1884, P- IO 5- 



Goebel Flora, 1882, p. 323. 



Firtsch Ber. Deutsch. Bot. Gesell., 1883, p. 83. 



Satter Ber. Deutsch. Bot. Gesell., 1884, p. 13. 



Haberlandt Ber. Deutsch. Bot. Gesell., 1883, p. 263 ; and Pringsheim's Jahrb. wiss> 



Bot., 1886, p. 359. 



Magdeburg Die Laubmooskapsel als Assimilations-Organ, 1886. 

 Vaizey (Sporogone) Ann. of Bot., i., 1887, p. 73. 

 Limpricht Die Laubmoose, in Rabenhorst's Crypt.-Flora Dsutschland, 1885-1888. 



The Musci are classified under four orders, as follows. The Sphag- 

 nacese exhibit much more important peculiarities than the other three 

 orders, and are ranked by some writers of authority as a distinct class. 



ORDER i. BRYACE^E. 



This order includes the vast majority of the genera of mosses, and 

 all the more familiar forms except the bog-mosses. The sporanges or 

 ' fruits ' form objects of great beauty in the autumn and winter, their 

 usual period of maturity, fertilisation taking place in the spring or early 

 summer. In some species the sporogone requires more than a year for 

 its full development. The sporogone consists of a sporange which is 

 always surmounted by a calypter, easily removed by the wind ; beneath 

 this is the opercule, which becomes detached, either alone qr together 

 with the annulus, a circular layer of hygrometric epidermal cells between 

 the opercule and the edge of the capsule; the whole elevated on a 

 longer or shorter stalk or seta, which is inserted at its lower end in the 

 vagine. The portion of the seta concealed in the vagine is known as 

 the foot, and acts as a kind of root, all the food-material needed for the 

 development of the sporogone being absorbed through it. The central 

 strand of tissue in the seta of the Polytrichacese consists, according to 

 Vaizey, of two portions a leptophloem or rudimentary phloem, in which 

 the storing up and conduction of the food-material takes place ; and a 

 leptoxykm or rudimentary xylem, which serves for the conduction of the 

 transpiration-current to the lower portion of the sporange furnished 

 with stomates. In the Polytrichacese, in addition to the opercule, a 

 horizontal layer of cells termed the epiphragm remains attached to the 

 points of the teeth of which the peristome is composed, and covers the 

 mouth of the sporange after the removal of the opercule. The sporange 

 is penetrated by a complete axial columel. The spores are formed by 

 free-cell formation in fours within spore-mother-cells, themselves derived 

 from a single primordial layer, the archespore ; the walls of the spore- 

 mother-cells finally deliquesce, leaving the spores floating in a fluid 



