THE FUNGI WHICH CAUSE PLANT DISEASE 393 



Basidia free on the end of the hyphse 



without saccate cell l. Stypinella, p. 393. 



Basidia subtended by a saccate cell 2. Saccoblastia. 



Sporocarps crustaceous H. Platygloeeje. 



Sporocarps gelatinous, auriform or cap- 



sbaped in. Auricularieae, p. 393. 



In tribe III, AuricularieEe, there is a single genus, Auricularia. 



Cap more or less cup-shaped or ear-like, jelly-like but firm when 

 wet, homy when dry, the hymenium often veined or folded, but 

 without teeth. The name refers to the cup-like form. 



A. auricula-judise (L.) Schr. is a very common saprophyte which 

 is occasionally parasitic on elder, elm, and mulberry in Europe. 



In tribe I, few cases of parasitism of any importance are reported. 



Stypinella mompa (Tan.) Lin. is foimd on the roots of mulberry 

 in Japan. 



Eubasidii (p. 299) 



The Eubasidii represent the higher development of the basidia- 

 fungi and contain the majority of the species. The basidia, 

 the typical club-shaped undivided stalks, bear usually four, 

 sometimes two, six, or eight unicellular spores on a like num- 

 ber of sterigmata and are mostly arranged in hymenia. There 

 is great diversity in the form and size of the sporophore from 

 an almost unorganized mycelial microscopic weft to the large 

 complex structures of the toad stools and puff balls. Conidia 

 and chlamydospores while occasionally present are much less 

 common than in the preceding groups or orders. 



The cells of the sporophore in many forms investigated are 

 binucleate;'' in other forms they are multinucleate. 



The origin of the binucleate condition often antedates the for- 

 mation of the sporophore and may occur far back in the mycelium, 

 perhaps as far back as the germinating basidiospore itself.'*' '^' '^ 

 In the basidial layer, however, even of those forms with multi- 

 nucleate vegetative cells, the nuclei are reduced to two so that 

 the general statement is permissible that in the hymenial layer 

 of the Basidiomycetes the cells are binucleate. From such cells 

 two nuclei wander into the basidium primordium where they 

 fuse to one, reducing this cell to a uninucleate condition. This 



