234 



ANNALS OF SCOTTISH NATURAL HISTORY 



I have to express my obligations to members of the staff of 

 Kew Herbarium for assistance in several instances. 



My readers may be reminded that the summer of 1893 

 was very warm and dry ; while the winter 1 894-95, especially 

 after Christmas, was exceptionally severe, with long-continued 

 extremely low temperatures. 



