V. 



MOSSES (MUSCI): SPHAGNALES—ANDREALALES 169 



formed by the active division of the cells, in a manner probably 

 entirely similar to that in other Mosses, and this rapidly as- 

 sumes the form of the young stem. The first leaves are very 

 simple in structure, and are composed of perfectly uniform 

 elongated quadrilateral cells, all of which contain more or less 

 chlorphyll. Like the older ones, however, they show the char- 

 acteristic two-fifth divergence. Schimper states that the fifth 

 leaf, at the latest, shows the differentiation into chlorophyll- 



A. 



Fig. 89. — Sphagnum cymbifolium. A, Median longitudinal section of a slender branch; 

 X, the apical cell; B, part of a section of the same farther down, showing the 

 enlarged cells at the bases of the leaves, and the double cortex (cor) ; C, cross- 

 section near the apex of a slender branch; D, glandular hair at the base of a 

 young leaf — all X525. 



bearing and hyaline cells, found in the perfect leaves. The 

 first leaves in which this appears only show it in the lower part 

 the cells of the apex remaining uniform. 



