THE ANCIENT FERNS 



With regard to Hymenophyllum, H. unilaterale Bory was fixed in the field in Borrowdale 

 in the Lake District in early July. Its chromosomes are shown in Fig. 274(2 and they are 

 very surprising. In spite of the minute size of the plant they are the largest individual 







1^ 



Fig. 271. Meiosis in Trichomanes radicans Sw., permanent acetocarmine. x 1000. 

 For explanatory diagram see Fig. 272. n—']2. 



Trichomanes " n -72 



Fig. 272. Explanatory diagram to Fig. 271. x 1500. 



chromosomes yet recorded in the Pteridophyta and their number is only n= 18. The 

 same kind of surprise can be felt in viewing H. tunbridgense (L.) Sm. (Fig. 274^). This 

 was fixed in the moss house of Glasgow Botanic Garden which seems to suit it unusually 



272 



