96 



ELEMENTARY STUDIES IN BOTANY 



fact that it does not produce leaves. Like the stem, it often 

 branches, and this means a greater capacity for receiving 

 water. It must not be supposed that all roots are in the soil, 

 for some roots are produced in the air by climbing stems, and 

 anchor the stems to supports. In this case they simply act 

 as holdfasts and do not receive water, but they can be recog- 



FIG. 76. Under surface of fern leaves, showing sori : A, elongated sori ; B, round sori. 



nized as roots by the vascular cylinder and by the fact that 

 they do not bear leaves. 



58. The sporangia. A sporophyte, whether dependent 

 or independent, must bear spores, and these spores must be 

 placed in a favorable position for dispersal by air. In the 

 dependent sporophyte of Bryophytes, the conspicuous part 



