CRYPTOGAMOUS PLANTS. 243 



anthers, and especially in the dioecious capitula; but 

 nothing prevents our admitting (and several say that 

 they have seen it) that at this period the calyptra is 

 slightly open at the apex, or we might believe at least 

 that there is some direct communication with the stiarma. 

 It has also been said, that the mode of fecundation 

 described above is impossible in aquatic Mosses; but 

 Hedwig has remarked that when they flower, which is 

 very seldom, the tops are then raised above the water. 



Beauvois has maintained, that the whole reproduction 

 of Mosses is performed in the theca alone, partly found- 

 ing his opinion upon the very small number in which 

 male organs have as yet been perceived. He thinks that 

 the seeds of Hedwig were the pollen, and that the true 

 seeds were inclosed in the columella. As an objection to 

 this theory, has been urged the improbabihty of finding 

 the pollen at the same time as the ripe seeds, so per- 

 fectly resembling them in size and form, and in so great 

 a quantity; it has been especially answered by the germi- 

 nation of the pretended grains of pollen. Finally, 

 Mr. Robert Brown appears to have found the cause of 

 the illusion of Beauvois; when the theca is cut trans- 

 versely, the knife carries with it into the columella some 

 of the seeds, which are those which he believes are 

 lodged there ; but when the columella is either cut 

 lengthways, or after having completely isolated it, we 

 find nothing but cellular tissue devoid of seeds. 



Besides the sexual reproduction which we have de- 

 scribed, Mosses are also propagated by shoots which 

 proceed from the trunk, and taking root, form new indi- 

 viduals. This mode is common in aquatic Mosses, and 

 those of very damp places, which rarely flower. 



B -' 



