108 MUSCALS. [BOOK i. 



period of the maturity of the sporangium. At this time 

 both membranes are occasionally obliterated ; but this is 

 an unfrequent occurrence : sometimes one membrane only 

 remains, either divided into divisions, called teeth, which are 

 always some multiple of four, varying from that number as 

 high as eighty, or stretching across the orifice of the theca, 

 which is closed up by it ; this is sometimes named the 

 epiphragma or tympanum. Most frequently both membranes 

 are present, divided into teeth, from differences in the number 

 or cohesion of which the generic characters of mosses are in 

 a great measure formed. For further information upon the 

 peristomium, see Brown's remarks upon Lyellia, in the 

 twelfth volume of the Linnean Transactions. 



M. Endlicher considers that the sporangium is formed by 

 the adhesion of an external and internal series of organs ; 

 and he calls sporangidium the inner, to which the peristo- 

 mium belongs. (Genera Plantarum, 46.) The interior of 

 the sporangium is commonly unilocular; but in some species, 

 especially of Polytrichum, it is separated into several cells by 

 dissepiments originating with the columella. If at the base 

 of the sporangium there is a dilatation or swelling on one 

 side, this is called a struma ; if it is regularly lengthened 

 downwards, as in most of the Splachnums, such an elonga- 

 tion is called an apophysis. 



The spores have no adhesion either to the sides of the spo- 

 rangium or to the columella, but appear to be formed much 

 in the same way as pollen. When they germinate they pro- 

 duce capillary, articulated, green, branched threads, resem- 

 bling Confervse ; and the leaves eventually appear from the 

 axils of such branches.* 



From the foregoing description, it will be apparent, that 



* "Mr. Drummond, in a paper published in the 13th volume of the Linncean 

 Transactions, proved, beyond a doubt, that the sporules of mosses germinate by 

 emitting ' pellucid filaments ' from any points on their surface. I have myself 

 examined the germinating sporules of Funaria hygrometrica, and I found that 

 the brown coat burst sometimes in two or three places, but most frequently in 

 one only ; and there protruded from each fissure a delicate transparent tube 

 containing the moving particles, which had previously occupied the cavity of the 

 sporules. These tubes, or, to speak with more precision, elongated cells, gra- 

 dually increased in length, and, from exposure to light, became of a green colour. 



