566 TEXTBOOK OF BOTANY 



place through the dissemination of minute propagules containing both 

 the fungous hyphae and the alga. 



Fungi Imperfecti. These are fungi in which zygotes, ascospores, or 

 basidiospores either are not formed or have not yet been discovered. 

 Nearly 24,000 species are now referred to this group. Here belong, for 

 example, the fungi that cause the leaf spot of beets, "athlete's foot," and 

 early blight of potato. 



GENERAL REFERENCES 



Brown, W. H. The Plant Kingdom. Ginn and Company. 1935. 



Dodge, C. W. Medical Mycology. C. V. Mosby Company. 1935. 



Fink, B. The Lichen Flora of the United States. Univ. of Mich. Press. 1935. 



Gwynne-Vaughan, H. C. I., and B. Barnes. The Structure and Development 

 of the Fungi. 2d ed. Cambridge Univ. Press. 1937. 



Krieger, L. C. C. The Mushroom Handbook. The Macmillan Company. 1935. 



Macbride, T. H., and G. W. Martin. The Myxomycetes. The Macmillan Com- 

 pany. 1934. 



Raper, J. R. Sexual hormones in Achlya. Amer. Jour. Bot. 26:639-650, 1939; 

 Amer. Jour. Bot. 27:162-173. 1940; Science. 89:321-322. 1939. 



Smith, A. L. Lichens. Cambridge Univ. Press. 1921. 



Smith, G. M. Cryptogamic Botany. Vol. I. McGraw-Hill Book Company, Inc. 

 1938. 



SELECTED READINGS 



Colley, R. H. The telephone pole and the mushroom. Sci. Monthly. 38:378- 



383. 1934. 

 Lambert, E. B. Principles and problems of mushroom culture. Bot. Rev. 



4:397-426. 1938. 

 McCubbin, W. A. Fungi and Human Affairs. World Book Company. 1924. 

 Pray, L. L. Common mushrooms. Botany Leaflet No. 18. Field Museum of 



Natural History. 1936. 

 Stakman, E. C, W. L. Popham, and R. C. Cassell. Observations on stem rust 



epidemiology in Mexico. Arner. Jour. Bot. 27:90-99. 1940. 



