146 THE SCOTTISH BOTANICAL REVIEW 



crags are specially influenced by frost, wind, mist, drip, and 

 snow lie ; the coastal crags by erosion, salt spray, insolation, 

 wind, and manuring by sea-fowl, and river crags by erosion, 

 inundation, spray, and the degree of exposure to light. 



REFERENCES. 



(38) Oliver, A. W.— " The Shingle Beach as a Plant Habitat." 



The New Phytologist, vol. xi., March 19 12. 



(39) Smith, R. and W. G. — "Botanical Survey of Scotland : Forfar 



and Fife." Scot. Geograph. Mag., 1904. 

 (4.0) West, G. — " A Comparative Study of the dominant Phanero- 

 gamic and Higher Cryptogamic Flora of Aquatic Habit in 

 Three Lake Areas of Scotland." Proc. Roy. Soc. Edin., 

 vol. XXV. part, xi., 1904. 

 West, G. — "A Further Contribution to a Comparative Study 

 of the dominant Phanerogamic and Higher Cryptogamic 

 Flora of Aquatic Habit in Scottish Lakes." Ibid., vol. 

 xxx. part ii., 1909. 



(41) Smith, W. G. — '■'■ Anthelia : An Arctic-Alpine Association." 



Scot. Bot. Review, No. 2, April 191 2. 



(42) ToPLEY, W. — "Geology of the Weald." Memoirs of the 



Geological Survey of England and Wales. 

 Reid, C. — "Geology of the Country around Eastbourne." 

 Memoirs of the Geological Survey of England and Wales. 



(43) For the physiographic ecology of sand-dunes see in particular 



Cockayne. 



(44) Oettli, M. — " Beitrage z. Okologie der Felsflora," Ziirich, 



1905. 



Caithness Lichens. By Rev. D. LiUie, B.D. 



The following is a list of lichens gathered by me in 

 Caithness (v.c. 109). In the case of some of the rarer species 

 which I have gathered only once or twice, I have stated the 

 locality. 



I have to thank those who have assisted me in determining 

 the specimens. I am especially indebted to Dr. Bouly de 

 Lesdain of Dunkerque, France, who has examined for me a 



