56 



L. COCKAYNE 



merely, for in a number of individuals, which had leaves growing 

 both in sun and shade, the sun leaves had strongly pouched seg- 

 ments, while those of the most intensely shaded leaves were quite 

 flat, and various intermediate stages of " pouching" in harmony 

 with the intensity of the illumination were present. In the case 



Fig. 2 Upper part of frond of Hymenophyllum Malingii. Photograph by L. 

 Cockayne. 



of Gleichenia circinata and G. dicarpa, unless there are other differ- 

 ences of specific value, the two " species" must be united, nor 

 can either the form with flat segments or that with pouched be 

 kept distinct, even as varieties. 



A very similar case occurs amongst the spermophytes in Olearia 



