ASCOMYCETES 253 



sufficient to prevent the spread from occasional outbreaks. Since, 

 however, wild plums and cherries everywhere may be affected, 

 eradication is difficult. In many regions the fungus is so com- 

 mon and so persistent that it is necessary to take additional pre- 

 cautions. Spraying with Bordeaux mixture has been advised, and 

 where spraying is given, one application should be made during 

 the late winter and one when the buds begin to swell. This latter 

 should be followed by two or three subsequent applications as may 

 seem necessary. It has been thoroughly demonstrated, however, 

 that the disease is controllable, and when cooperation is given, 

 eradication in large areas is perhaps possible. 



XXXIX. SPHyERIALES 



The sphaeriaceous Ascomycetes constitute an order (sometimes 

 considered a suborder) containing more species than perhaps any 

 other equivalent natural group of the fungi. The great majority 

 are saprophytic in habit, occurring upon decaying twigs, leaves, 

 and, in fact, upon practically all kinds of vegetable matter, or 

 upon the soil. There are some notable parasitic species, but 

 these are relatively inconsiderable as compared with the great 

 number of saprophytes. 



The mycelium may be light or dark colored, usually the latter, 

 and the perithecia show very diverse characters with respect to 

 texture and form of the ostiolum, as also with relation to the sub- 

 stratum and stroma. They may be free, slightly connected by a 

 scant subiculum, or more or less imbedded in a stromatic tissue 

 of variable texture. The perithecia vary from membranous to 

 carbonaceous, delicate, tough, or brittle, and the ostiolum may 

 be merely a circular aperture, a slight papillate opening, or a 

 long beak. What has been said of conidial stages under the 

 Ascomycetes in general applies in particular to this group, these 

 stages being manifold, so far as the method of conidiospore pro- 

 duction is concerned. 



This order is commonly subdivided into eighteen families, 

 which differ from one another, however, in characters so slight 

 that a brief key of those which are here to be considered may 

 be sufficiently descriptive. 



