GERMINATION OF THE SPORES. 89 



Huddiiiu- of the ascospori's i)cc-iirs citluM- lu'forc or tiftcr tlu> cscjipc 

 of the spores fioiu the useiis. In the fonnation of the hud eonidia the 

 process may take phice from the ascospore direct, one conidium after 

 another bein^- produced, oi' the contents of the ascospore mny pass into 

 a thin-walled conidium nearly or (piite ecjual in size to the ascospore, 

 this lai"ge conidium then assuming the function of l)ud production. 

 Ordinarily the ascospore huds at one point only, but l)ud formation at 

 two points has been seen. Buddino- occurs most conunonly at one end 

 of the ascospore, l)ut occasionally lateral buds are ol)served. In the 

 early stages of l)uddin(^ tiie ascospore sometimes shows a nii)ple-like 

 swellint^ at one end, reminding one of the germinating end of the 

 sporangium in the PeronoajMyi^ecB. The successive primary conidia bud- 

 ding from an ascospore may become loosened and turned to one side 

 by the following conidium, which swells from the same germ pore of 

 the ascospore. In other cases several conidia maj" remain united with 

 each other, but when this condition is observed it is frequently the 

 result of the secondary or tertiary budding of the primary conidium, 

 several orders or generations of buds remaining united. \Mien the 

 process of primary conidial ))udding can no longer take place the empty 

 ascospore may or may not become separated from the last primary 

 conidium. With the exception of the case above referred to, the dif- 

 ferent orders or series of conidia (primary, secondary, tertiary, etc.) 

 when grown in pure water, are each smaller than the preceding, and 

 the conidia are considera))ly elongated in form, sometimes almost 

 cylindrical. The walls of the conidia are mori^ delicate than those of 

 the parent spore. In a suital)le nourishing fluid, as the extract of malt, 

 the conidia take up nourishment and increase in size, thus enabling 

 them to continue the budding process for considerable periods of time, 

 as in the yeasts (Saccharomyces). Whether the conidia of Exomcm 

 defm'Tnans are able to induce an alcoholic fermentation through their 

 growth in saccharine culture media is not known, but Sadebeck states 

 that the conidia of other species of this genus certainly possess this 

 fermenting power. 



The second method of germination of the ascospore of Exoascus 

 defm'mans, that is, the pushing of germ tubes, is rarel}^ met with 

 except upon the host plant itself. Such mode of germination is shown 

 in PI. IV. The germ tube produced from the ascospore is usually 

 much swollen near the spore and tapers considerably toward the 

 extremit} % though not infrequent!}^ considerable constrictions occur 

 at one or more points in its course. It seems probable that this tube is 

 in man}' cases capable of directly infecting the host, probably through 

 a stoma, as observed by Sadebeck in Exoascus tosquinetii, and that its 

 function is not wholly the abjointing of sporidia. Such separation of 

 sporidia, in fact, has not thus far f^een observ^ed. The germ tube, 

 or promycelium, is connected with the spore by a very narrow and 

 short tube, with straight and ])arallel walls. The same mode of con- 

 nection is also observafjle in the formation of the bud conidia, and 



