.312 VEGETABLE ORGANOGRAPHY. 



but 110 full-grown leaf is ever divided; This structm-e 

 is only met with in the primordial or radical ones of 

 a small number of Mosses, such as Phascum cohcerens ; 

 these leaves are irregularly divided into slender processes, 

 composed of cellules placed end to end, the partitions of 

 which are visible with a lens. 



The absorption of water is performed by Mosses with 

 singular facility, and when one which has been dried 

 for a long time is plunged in, it regains the freshness 

 and appearance of life. Some have even asserted that, 

 like the Rotiferse, dry and dead plants may be restored 

 to life by being placed in water ; but this important fact 

 does not appear to have been sufficiently demonstrated. 

 When only half of a dried Moss is dipped into water, 

 the submerged part acquires the appearance of life, and 

 the other continues dry ; this fact, of which we shall 

 find numerous examples in the following families, tends 

 to show that the effects of absorption in cellular plants 

 are much more local than in %'ascular ones. Finally, 

 there is no doubt that, in the ordinary state of their 

 vegetation, they absorb much water by their foliaceous 

 surface ; it is probable that this is their principal means 

 of nutrition ; that their life is preserved for a long time 

 in a state of torpor, and can be reanimated by rain or 

 immersion : this frequently happens to perennial ones, 

 which only grow well in a moist season, and appear 

 dried up in summer. Whence comes this faculty? it 

 is the subject of doubt above mentioned. 



Leaves, which perform, as we have seen, so important 

 a function in these plants, are hardly ever absent. Bux- 

 haumia aphylla alone appears entirely devoid of them, 

 and its vegetation is a peculiar mystery, at least in its 

 infancy. 



I have already described the ordinary structure of the 

 leaves of Mosses ; but there happens in some species of 



