80 A Monograph of. the Erysiphaceae 



2. Appendages colored for half their length or more. ' 5. jiecaior. 

 Appendages colored only at base (up to the first septum). 16. aitsiraliana. 



3, Asci 2-3-spored. ■ 4, 



Asci 4-8-spored. 6, 



4". Asci more than 30, perithecia very large, 215-320 // in diameter. 12. polychaeta, 



Asci 4-20, perithecia 85-165// in diameter. 5. 



5. Appendages 9-25, perithecia average 95// in diameter, asci 3-6. 4. clandesiina. 

 Appendages 50-130, perithecia average 130//, asci 8-20. 8. niacrospora. 



6. Appendages all simple. ' y^ 

 Appendages some or all branched. 20. 



7. Appendages delicate, narrow, 3-4 /^ wide, asci 4-7-spored, 8. 

 Appendages stouter, wider, or if narrow with asci 8-spored. lo. 



8. Asci about 25, perithecia 150-200 /i in diameter. 13. confusa. 

 Asci 5-8, perithecia 86-122 fi in diameter. o. 



9. Appendages 50-160, }4~)^ diameter of perithecium. 7. paii'ida 



Appendages 24-46, i^-a diameter of perithecium, often geniculate. \l, genie id at a. 

 10. Appendages stout, 7-8 a wide near the base. il. 



■ 



Appendages narrower near the base. 



12. 



11. Appendages very few, 6-12, enlarged upwards. 15. Delavayi. 

 Appendages crowded, 20-36, scarcely or not at all enlarged up^vards. 



18. SettgokitL 



12. Appendages abruptly flexuose or angularly bent. -, 13. 

 Appendages straight. j^^ 



13. Appendages about equalling diameter of perithecium, flexuose above, not angularly 



bent, spores usually 8. 9^ Jlexuosa, 



Appendages 1-2, usually i;i-2 diameter of perithecium, more or less angularly 



bent, spores 4-6, rarely 7. I. salicis.vzx. Miyabeu 



14. Appendages thick-walled, refractive, or rough at base. 15 

 Appendages thin-walled throughout. 17, 



15. Mycelium persistent, densely compacted, perithecia 156-268 p, in diameter. 



2. acerisy var. Tuiasnei, 

 Mycelium evanescent or subpersistent, perithecia 64-146 ft in diameter. 16. 



16. Asci ovate or elliptic-oblong, 24-30 ^ wide, spores 16-20 X 8-I0 p. 3. prunastri. 

 Asci broadly ovate to subglobose, 34-40 /i wide, spores 20-25 X 10-13 j«- 



17. Asci 4-6-spored. . . - . 



^ ■ 



Asci 7-8-spored. 



18, Perithecia 168-224 I'- in diameter, appendages not exceeding diameter of perithe- 



I T 



6. ch'cmaid. 



lo. Clintonii. 

 I. salicis. 



18- 



cmm. 



dianieter 



cium. 



19. 



19. Penthecia 120-13S ^ m diameter, appendages 35-60. mycelium persistent, more 



or less densely compacted. - 14. australis. 



Perithecia 76-105 /^ in diameter, appendages 10-28, mycelium evanescent. 



17. fraxin'u 



20. Mycelium densely compacted, appendages mostly simple. 2. aceris, var. Tuiasnei^ 



jMycelium not densely compacted, appendages all or nearly all branched. 



2. aceris. 



