FACTORS OF INCREASE 



123 



FIG. 64. 



a, I', c, j, k = Gleichenia flabellatn, Br. d, e, f=Gl. circinata, Sw. g, /i, i=Gl. 

 dichotoma, Willd. a, b, c, d, show young sori with sporangia marginal, g shows a 

 similar condition in Gl. dichotoma, but in h and i the vacant middle space is occupied by 

 young sporangia. ^1-2X200. /, xioo. 



B 



jfr 



Fu;. 65. 



A, B, Dennstaedtia afiifoiia, Hook. A shows the regular basipetal succession of 

 sporangia characteristic of the (Iradata;. C, D, Dennstaedtia nibiginosa, Kaulf. D 

 shows irregularity in the succession, x 100. 



