Fig. 44.— The Brake (Pteris aquiUna), showing part of the underground stem (r.?J> 

 and two leaves, one (?'), of the present year, in full development; the other 

 d'), of the past year, dead and withered, a.b, apical bud at the extremity of a 

 branch which bears the stumps of leaves of preceding years and numerous- 

 roots; P, mature active leaf ; P, dead leaf of preceding year ; l.m, lamina of leaf ; 

 p, pinna ; r.h, portion of main rhizome ; ;r, younger pinna, which is shown en- 



larged at B. This pinna is nearly similar to the pinnules of older pinnae. 



(Xi.> 



