ORDER MONILIALES (hYPHOMYCETEAE) 



595 



Fig. 201. Moniliales, 

 Family Dematiaceae. (A) 

 Cercospora zeae-maydis Tehon 

 & Daniels. (B) Cladosporiurn 

 fulvum Cke. (A, after Tehon 

 and Daniels: Mycologia, 

 17(6):240-249. B, after Pril- 

 lieux and Delacroix, Bull, 

 soc. rnycol. France, 7(1) :19- 

 21.) 



Polythrincium (Phaeodidymae) produces its dark-colored wavy conid- 

 lophores in tufts emerging through the epidermis of the host leaf. They 

 bear apically the colored two-celled conidia. P. trifolii Schm. & Kze, is 

 parasitic on the leaves of clover {Trifolium). Wolf (1935) has proved that 

 the perfect stage of this fungus is Cymadothea trifolii (Pers.) Wolf, so that 

 really this species should no longer be given consideration under the 

 Fungi Imperfecti but under Order Dothideales in the Ascomyceteae. The 

 genera Hormodendron and Clados'porium although maintained separately 

 in the reference books are scarcely worthy of distinction. In both' of them 

 the conidiophores are colored, septate, and variously branched. Near the 

 tip the branches are more numerous and bear acrogenously produced 

 chains, often branching also, of conidia. In Hormodendron these are one- 

 celled, in Cladosporium the younger spores are one-celled and those 

 further down in the chain may become two-celled and sometimes three- 

 to four-celled. (Fig. 20 IB.) Some species of the former represent the stage 

 in culture on artificial media of certain of the pathogens of Man that 

 cause a serious disease of the skin known as dermatitis verrucosa (see 

 Emmons and Carrion, 1937). The genus Cladosporium with over 160 

 described species is an assemblage of species representing many different 

 and probably not properly congeneric types. C. herbarum Link ex Fr. is 

 found the world over on dead organic material and apparently occurs 

 sometimes as a plant parasite. It probably does not represent a single 

 species but a host of closely similar and very variable species. The perfect 

 stage of one form has been described as Mycosphaerella tulasnei Jancz., 

 parasitic on various cereals. Another very dissimilar parasitic species is 

 C. cucumerinum Ell. & Arth., with rather short, unbranched conidio- 



