238 ILLINOIS ACADEMY OF SCIENCE 
fifty-nine species the presence or absence of paraphyses is not 
mentioned. The stroma does not present sufficient variation 
to render it of much use for classification. The basis for 
specific differentiation thus lies chiefly in the character of the 
asci and spores. There is great variation in size and form of 
spores. The minimum spore length is 6 » in the species P. 
poae, and the maximum 40 » in P. dasylirit. There is also 
great diversity in spore form since in P. dolenchogena the 
spores are globular, in P. dentritica ovate and in P. lonchotheca 
the length of the spore is about six times its width, P. bum- 
busina, P. stenostoma, and P. oxalina have 1-septate spores, 
which is an exception to the generic character of continuous 
spores. 
In as many as twenty-five instances two to six species have 
identical spore measurements. (e. g. P. astrocaryi, P. trop- 
icalis, P. bromi, P. lagerheimiana). In some cases species hav- 
ing the same spore measurements are found on the same host 
family (e.g. P. asprellae, P. pazschkeana.) In one species 
only (P. ficicolag is there variation from the usual spore num- 
ber of eight. In this species there are asci having four spores. 
In the revision of the genus by Sydow and Theissen” the 
number of species has been reduced to three hundred and 
twenty-nine. Form classification based upon the position of 
the perithecia in the host, fifty-two species have been removed 
to the genus Catacauma, eleven to the Genus Trabutia and four 
to the genus Bagnisiopsis, while a large number have been 
removed to other genera. 
Fig. 7. Mycelium in newly invaded cell. 
