402 THE DEUTEROMYCETES (FUNGI IMPERFECTI) 



especially in tropical and subtropical regions, are of equal 

 interest. Wolf and Bach (1927) regard this species as identical 

 with C. stevensii on the basis of similarities in morphologic and 

 cultural characteristics and on ability to produce reciprocal in- 

 fections. Others, including Matsumoto and Yamamoto (1935), 

 maintain that there are two separate species, mainly because of 

 differences in sclerotial production. It does not seem reasonable, 

 however, in view of the fact that sclerotia form sparsely on 

 smooth surfaces and abundantly on rough surfaces, as on the 

 fruit of Stavman apples and russet apples, respectively, and that 

 strain differences \\ithin many single species of fungi are known, 

 to regard C. koleroga and C. stevensii as distinct. 



Ozonium possesses loose, bright yellowish masses of mycelium 

 that may unite into strands. Its best-known species is O. omniv- 

 onim, commonly called the Texas root-rot fungus; its known 

 host range includes approximately 500 species of herbaceous and 

 woody plants, the most important of which is cotton. Sclerotia 

 form in abundance in the soil. Sometimes a conidial stage, known 

 as Fhymatotrichimi ommvoriim, is produced in large buff-colored 

 patches over the soil surface in areas where cotton has been 

 killed by this root-rot fungus. 



Pachvma includes fungi having enormous subterranean scle- 

 rotia that have been used for food. Several have been connected 

 with polypores. F achy ma cocos, having sclerotia that may weigh 

 more than 20 lb, but more commonly weis^h 1 to 8 lb, was shown 

 bv Wolf (1922) and Weber (1929) to be the sclerotial stage of 

 Foria cocos. Tai and Wei (1933) reported the occurrence of 

 this species in China, where it is known as fuhling or Chinese 

 root and is used medicinally. It is cultivated on buried pine 

 poles, the annual crop being more^than 1000 tons. Related spe- 

 cies include "black-fellow's bread," Folyporus my lift ae of Aus- 

 tralia, F. sapiirejna of southern Brazil, whose sclerotia may attain 

 a weight of 40 lb, P. tiiberaster of Italy, and the more recently 

 described P. tiickahoe of Canada [Giissow (1919)]. 



In summary, the Fungi Imperfecti are of unusual interest to the 

 student of problems involving pleomorphism and complicated 

 developmental cycles. Even after several hundred more years of 

 study by many mycologists it is probable that not all these prob- 

 lems will have been solved. 



