Davis — Parasitic Fungi in Wisconsin — I. 81 



Phleospora aceris (Lib.) Saec. and with this have been included 

 narrower spored forms but usually the latter have been referred 

 to Septoria. Diedicke has recently referred the European forms 

 with sporules 3/a or less in thickness to Cylindrosporium, recog- 

 nizing three species. (Ann. My col. 10:4:86 (Oct. 1912) ). Sep- 

 toria saccliarina E. & E., however, while producing similar spor- 

 ules develops pycnidia in definite arid spots but Cylindrospor- 

 ium saccharinum Ell. & Ev. agrees with the form on Acer rub- 

 rum which was recorded in the "provisional list" under the 

 name Phleospora aceris (Lib.) Sacc. 



Septoria musiva Pk. The specimens of Septoria that have been 

 collected on Populus in Wisconsin may be divided into groups as 

 follows : 



1. Spots subcircular to subangular, black becoming white and 

 arid except the peripheral portion, 3-5 mm. in diameter ; pycni- 

 dia epiphyllous, superficial-collapsing, hemispherical in section, 

 about 100/a in diameter; sporules cylindrical, curved, obtuse, 

 3(2^) septate, 25-60 x 2-3/*. On Populus balsamifera. 



2. Similar to the above except that the central portion of the 

 spot becomes alutaceous or cinereous instead of white and the 

 pycnidia are more scattered and lie deeper. Also on P. balsami- 

 fera. 



3. Spots subcircular to angular, limited by the veinlets, at 

 first brown, becoming grey by the loosening of the cuticle, 1-3 

 mm. in diameter, becoming confluent into larger areas, %-l cm. 

 in diameter; pycnidia innate, discharging on either surface but 

 usually below, having a thin but distinct wall and a large open- 

 ing, TO-lOOjU. in diameter; sporules cylindrical, curved, obtuse, 

 3 (2-4) -septate, 25-65 x 2-3^. On Populus deltoides. 



4. Spots roundish to irregular and angular, dark brown above 

 becoming grey with age, light brown below, 2-5 mm. in diameter, 

 often confluent ; pycnidia hypophyllous, punctif orm ; sporules 

 cylindrical, curved, obtuse, 3-5 septate, 45-65 x 3//.. On P. 

 balsamifera. 



5. Spots angular, blackish brown above, paler below, becoming 

 lighter and mottled with age, y 2 -l cm. in diameter; pycnidia 

 scattered, innate, thin walled ; sporules filiform, narrowed to one 

 end, 3-6 septate, 40-70x1 1 / 2 -2 1 / ^^. On Populus tremuloides. 



In the provisional list all of these forms were included in Sep- 

 toria musiva Pk., although group 5 may prove to be distinct, but 



