FRONDS OR LEAVES 



77 



first instance the leaf is said to be once pinnate and in the 

 second instance twice pinnate. 



FIG. 41 . Filicaies. The upper left figure is a spore of evergreen wood-fern. 

 The next three figures show the growth of the protonema. The lower left 

 figure shows the prothallium which bears the antheridia and archegonia. To 

 the right of the prothallium are two figures showing the high power of the 

 cellular structure and a root hair. The three upper right figures show cross- 

 sections of a prothallium with antheridia and male gametes. The lower right 

 figure is a longitudinal section of an archegonium. 



