MILDEWS AND RELATED FUXGI 163 



are tMn and membranaceous to coriaceous, slightly transparent to 

 black and opaque. The asci are usually very delicate, surrounded 

 by long paraphj^es, or intermingled with them. The dark-colored 

 sj>ores are one- to many-celled, surrounded by a hyaline gelatinous 

 envelope, or ornamented with hyaline gelatinous spicula. The 

 SoRDAitLACiLE are entirely saprophytic and grow on manure, hence, 

 they are coprophUous fungi. Sf>ecial mechanical devices are shown by 

 the asci for eruptive spore discharge and the distance to which the 

 spores are shot may be between 5 and 9 cm.' 



Family 4. Chmtoioaces.. — ^This is a small family of two genera, 

 Chatomium and Bommerella, which are found on waste p)af)er, manure 

 and on small living fungi, which resemble the fungi of the familj' 

 Perisporiacea, if the mouth to the perithecium is wanting. Bom- 

 merella has three-cornered ascospores. The perithecia of such forms 

 as Chcetomium spirals and C. crispatum are pro\-ided apically with 

 masses of spirally wound ha-rs. 



Family 5. Svhm'riacem. — ^This important family includes parasitic, 

 or saprophytic fungi showing exceptional diversity on dead i>arts. 

 They have rounded perithecia with definite opening. The peridium is 

 e^^dent, mostly dark-colored, membranous to leathen,- never fleshy, 

 usually free from the substratum, or more or less depressed. A 

 stroma may or may not be present. Some authors include a number 

 of families which perhapts may be subordinated here and ranked as 

 subfamUies. RoseUinia quercina is a disease of oak seedlings. Myco- 

 sphterella fragari^B is the cause of leaf spot of strawbeny: M. strali- 

 formans produces leaf-splitting blight of sugar cane. Gmgncrdia 

 BidweUii is a most important f>arasite, being responsible for the black 

 rot of the grape and G. wucinii causes creinberr>- scald. Apple 

 scab and pear scab are due to the attack of Venturia pomi and VetUuria 

 pyrina. A serious disease of s3'camore leaves in the spring known as 

 anthracnose is caused by Gnomoniii veneia. 



Family 6. Valsace^. — The stroma of these fungi is black and is 

 formed in the substratum which is more or less altered. The peri- 

 thecia have a r^ular border and take various forms in the different 

 genera. The asci are cylindric and long-stalked, alternating with 

 paraphrases. Prcnidiospores are formed in pycnidia and conidiospores 



• GRiFFrrHS, David: The North American Sord.vriace*:. Memoirs of the 

 Torrey Botanical Oub, d. No. 1, May 7, 1901. 



