ORDEB SACCHAROMYCETALES 349 



the sterigmata and discharged violently, often with the production of a 

 droplet of water at the base of the spore just before its discharge. As in the 

 Subclasses Teliosporeae and Heterobasideae these spores are capable of 

 germination by repetition, i.e., by forming sterigmata upon which similar, 

 but somewhat smaller ballistospores are produced. In the first two genera 

 colonies are formed in which the usual mode of reproduction is by bud- 

 ding, as in yeasts, producing considerable mucilage. In the other two 

 genera true hyphae are produced and no budding occurs. Nyland (1949) 

 has described still another genus clearly belonging to this family, to 

 which he has given the name Sporodiobolus. Like Itersonilia the mycelium 

 has an abundance of clamp connections. The cells are binucleate. An 

 abundance of chlamydospores is produced in Sporidiobolus. These are 

 binucleate but soon the nuclei unite and the spore becomes golden-brown. 

 In the younger stages of growth the cells bud, as in yeasts, forming a 

 yeast-like colony similar to that of Sporobolomyces. No asci or ascospores 

 occur in any of the four genera. These fungi occur on leaves covered 

 with sooty mold or injured by insects or by fungus parasites, and fre- 

 quently may be isolated from the soil. The aerial ballistospores are 

 distributed by air currents. (Fig. 116.) 



In Sporobolomyces a carotinoid pigment is present so that the colonies 

 are red to salmon colored, but in Bullera the pigment is lacking and the 

 colonies are pallid to yellowish. Neither of these two genera normally 

 produces hyphae, but it should be noted that sometimes in Spor^obolo- 

 myces, in old cultures, a few short, branching hyphae may arise and on 

 them develop laterally and terminally the characteristic spore-bearing 

 sterigmata. In normal development the first extensive growth is by 

 budding. Later some of the surface cells send out one (or even two or 

 three) sterigma each, which in some cases may become forked. Perched 

 obliquely at the tip of the sterigma a usually asymmetrical spore is 

 formed, like a basidiospore on its sterigma. 



The genera Tilletiopsis and Itersonilia form definite hyphae but not 

 yeast-like colonies of budding cells. From these hyphae arise sterigmata 

 from which the spores are discharged as described above. In Itersonilia a 

 clamp connection is formed at every septum while these are lacking in 

 Tilletiopsis. 



Kluyver and van Niel (1924) suggested that this mode of spore dis- 

 charge of the aerial spores warrants the idea that these fungi may be very 

 much reduced Basidiomycetes. Buller (1933) investigated this process 

 more fully and accepted the idea. Lohwag (1926) and Guilliermond (1927) 

 did not agree with this suggestion because the cells of the then recognized 

 species are uninucleate and there is no fusion of nuclei prior to spore 

 formation, so that these cells can not be considered as much reduced 

 basidia. Buller, on the other hand, pointed out that in a number of the 



