APPENDIX VIII 725 



13. Apex of appendages often undivided, or irregularly one to two times dichotom- 

 ous. 3 aslragali. 



Apex more divided. (14) 



14. Appendages four to six times the diameter of the perithecium, branching 

 diffuse and irregular. 13 Bdumleri. 



Appendages two and one-half to five and one-half times the diameter of the 

 perithecium, apex more divided, branching closer. 2 euonymi. 

 1$. Branching of the appendages lax, irregular. (16) 

 Branching closer and regular. (17) 



16. Appendages two to four times the diameter of the perithecium, not contorted, 

 ultimate branches long, forming a narrow fork. 7 dijfusa. 



Appendages one to two times the diameter of the perithecium, more or less 

 contorted, branching more irregular, with short ultimate branches. 4 ahii 

 var. ludens. 



17. Apex of appendages with very short primary and secondary branches more or 

 less digitate. 5 grossiilaria. 



18. Apex with short, widely spreading, usually curved ultimate branches. 4 alni 

 var. lonicerce. 



Apex with long, straight ultimate branches, not widely spreading, i berberi- 

 dis. 



Key to the Species of Uncinula 



Brief Characterization. — Perithecia globose to globose-depressed; asci several, 

 two- to eight-spored; appendages simple, or rarely (U. aceris) once or twice 

 dichotomously forked, uncinate at the apex, usually colorless, rarely dark 

 brown at base or throughout. 



1. Appendages colored. (2) 

 Appendages colorless. (3) 



2. Appendages colored for half their length or more. 5 necator. 

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



3. Asci two- to three-spored. (4) 

 Asci four- to eight-spored. (6) 



4. Asci more than thirty, perithecia very large, 215 to 320;u in diameter. 12. 

 polychce-ta. 



Asci four to twenty, perithecia 85 to 165^ in diameter. (5) 



5. Appendages, nine to twenty-five, perithecia average 95^ in diameter, asci 

 three to six. 4 clandestina. 



Appendages fifty to one hundred and thirty, perithecia average 130^, asci 

 eight to twenty. 8 macrospora. 



6. Appendages all simple. (7) 

 Appendages some or all branched. (20) 



7. Appendages delicate, narrow, 3 to 4^1 wide, asci four- to seven-spored. (8) 

 Appendages stouter, wider, or if narrow with asci eight-spored. (10) 



8. Asci about twenty-five, perithecia 150 to 200/1 diameter. 13 conjtisa. 

 Asci five to eight, perithecia 86 to 12 2m in diameter. (9) 



