CLASSIFICATION S3 



knots. Other genera, such as Licea and Cribraria, possess no 

 capillitium. 



Classification. The classifications that have been proposed, 

 including those of Lister (1925), Jahn (1928), and Macbride and 

 Martin (1934), are all highly artificial. Different ordinal names 

 are given by each worker. Color of spores and presence of 

 capillitium and of lime are given great emphasis in ordinal group- 

 ings. Genera apparently closely related are often widely sepa- 

 rated, as must happen when characters whose significance is not 

 yet evaluated are employed in classification. In spite of these 

 limitations identification is not a difficult task, and the group 

 must be regarded as very inviting to the taxonomist. 



Implications. The many unsolved problems concerning 

 Myxomycetes are clearly stated in a recent review by Martin 

 (1940). These problems involve, among other factors, the ques- 

 tion of whether plasmodia fuse, the sexuality of representative 

 genera (only a few of which have been studied), the uncertainty 

 whether + and — swarmers exist, the nature of the pigments 

 and of color changes in plasmodia, the stimulus of fruiting, mor- 

 phogenic mechanisms, the factors governing endemism, the 

 causes of protoplasmic streaming and of amoeboid movement, 

 and the relationship of slime molds to other organisms. 



LITERATURE CITED 



Bary, Anton de, Die Mycetozoen (Schlemipilze) . Em Beitrag zur Kennt- 



nis der niedersten Orga?jis?7ie72. Leipzig. 1864. 

 BisBY, G. R., "Some observ^ations on the formation of the capillitium and 



the development of Physarella mirabilis and Stejiionitis fiisca,'' Am. J. 



Botany, i; 274-288, 1914. 

 Blomfield, J. E., AND E. T. Schwartz, "Some observations on the tumors 



of Vero?jica chmiaedrys caused by Sorosphaera veronicae,'' Ann. Bot- 

 any, 24: 35-43, 1910. 

 Camp, W. G., "A method of cultivating m)^omycete plasmodia," Bidl. 



Torrey Bota?j. Club, 55:205-210, 1936. 

 "The fruiting of Physanmi polycephahmi in relation to nutrition," Am. 



J. Botany, 24: 300-303, 1937. 

 Chupp, Charles, "Studies on clubroot of cruciferous plants," Cornell Agr. 



Expt. Sta. Bidl, 5<?7; 421-452, 1917. 

 CiENKowsKi, L., "Zur Entwickelungsgeschichte der Alyxomyceten," Jabrb. 



iviss. Botan., 3: 325-337, 1863. 



