LIVERWORTS AND MOSSES. 



53 



61. The origin of the leaves will be apparent upon com- 

 paring figures 64, 65, and 66. In Blasia (fig. 64) the thallus 

 is lobed, i.e., the edge has not grown equally, but continued 

 growing longer at certain 

 points. In Fossombronia ( fig. 

 65) the flattened thalloid 

 form is still evident, but the 

 lobing has become so deep 



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Fig 62. 



Fig. 63. 



Fig. 62.— Gametophyte of Hazztniiti XoTce-Hollandite. Besides the ordinary- 

 branches there are slender ones (flagella) with sparse minute leaves. Naturalsize. 

 — After Lindenberg and Gottsche. 



Fig. 63.— A, dorsal view; A', ventral view of a piece of fig. 6a, magnified about 12 

 diam., showing the stem, bearing two dorsal rows of large leaves and one ventral 

 row of small ones.— After I.indenberg and Gottsche. 



that the almost separate parts are usually called leaves. 

 In Noteroclada (fig. 66) the central axis is still more com- 

 pact, and has lost its flat form, becoming a rounded stem 

 from whose flanks arise regular outgrowths, the leaves, each 

 of which corresponds to one of the lobes of the thallus in the 

 other forms. 



Mosses. 



In the mosses the complexity of the mature vegetative body 

 is somewhat greater. It is always developed as a shoot differ- 

 entiated into stem and leaves. 



62. Rhizoids. — The shoot is anchored, as in the liver- 



