256 W. B. McDOUGALL 



since some prominent botanists have recently adopted the rather 

 pecuhar notion that Uchens are simply fungi. The word lichen, 

 however, has been used for a long time to mean the composite 

 structure that results from the symbiosis of lichen-fungi with al- 

 gae, and no very good reason has yet been given for changing its 

 meaning. A lichen-fungus is a fungus; it is not a lichen. There 

 is no more reason for calling a lichen a fungus than there is for 

 calling a mycorhiza a fungus; and it is just as absurd to call a 

 lichen-fungus a lichen as it would be to call a mushroom a 

 mycorhiza. 



LITERATURE CITED 



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(4) Curtis. D. D.: Nature and Development of Plants. 506 pp. New York. 



1914. 



(5) De Bary, A.: Die Erscheinung der Symbiose. 30 pp. Strasburg. 1879. 



(6) Gager, C. S.: Fundamentals of Botany, 640 pp. Philadelphia. 1916. 



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(8) Harshberger, J. W. : Mycology and Plant Pathology. 779 pp. Phila- 



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(9) Lundstrom, a. N.: Pflanzenbiologische studien. 2. Die Anpassungen der 



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(10) Pfeffer, W.: Physiology of Plants. English Edition. Oxford, 1899. 



(11) Warming, E.: Oecology of Plants. English Edition, Oxford, 1909. 



(12) Jost, L. : Lectures on Plant Physiology. English Edition. O.xford. 1907. 



