46 Bulletin 313 



Mycosph^rella sentina (Fr.) Schr. (= Septoria piricola 

 Desm., page 92). — On the leaves of pear and apple. In conidial 

 stage causes angular spots of various sizes (depending on host) 

 with ashy-gray centers surrounded by brown or black zone and 

 sometimes an outer purple zone. These color zones are frequently 

 lost in older leaves. Pycnidia ovate, minute, black, on both sur- 

 faces of ashy-gray centers ; conidiophores hyaline, conidia filiform, 

 usually curved, 2-septate 40-60 x 3-4 fi. Perithecia crowded, black, 

 numerous, on under side of dead spots of over-wintered leaves, long 

 ostiole, ertmipent, 80-110 yu; asci colorless, clavate, frequently 

 sUghtly curved, base variable in form, 60-75 x 11-13 (i; ascospores 

 fusiform, straight or very slightly curved, 1-septate, cells equal, 

 26-33 X 4 /A. 



202. Infected leaf of pear. 203. Conidia, 1/12. 20+. Perithecia, 1/12. 205. 

 Asci, 1/12. 206. Ascospores, 1/12. 



Pleospora hyalospora E. & E. — On the leaves of alfalfa.* 

 Causes brown to whitish, oblong or marginal leaf spots. Perithecia 

 scattered, depressed, hemispherical, papilliform ostiolum erumpent, 

 75-90 fx. Asci oblong, 75-85 x 35-40 fi. Ascospores oblong to ovate, 

 ends rounded, 3-6 sptate with one or more longitudinal septa, 

 slightly constricted at septa, 25-41 x 12-20 fx. 



Note : — It is well known that Altemaria is sometimes the conidial 

 stage of the species of this genus. We found an Altemaria con- 

 stantly associated with this species, but did not prove its connec- 

 tion by cultitre and inoculation. 



207. Infected leaves of alfalfa. 208. Ascus, 1/12. 209. Ascospores, 1/12. 

 210. Germinating ascospores, 1/12. 211. Perithecium, 1/6. 212. Cross-section 

 of leaflet showing Altemaria associated with Pleospora, 2/3. 213. Conidio- 

 phores of same, 1/12. 214. Conidium of same, 1/12. 215. Germinating spore 

 of same, 1/12. 



Physalospora cydoni^ Arnaud. — The perfect stage of Sphcerop- 

 sis malorum, page 78. 



^Apparent!}' the same as P. hyalospora reported on Lathyrus sativus and 

 Pisum sativum. 



