THE FUNGI WHICH CAUSE PLANT DISEASE 135 



hyaline. Some of the genera are among the most serious of 

 plant pathogens. About one thousand species. 



Key to Genera op Helotiacese 



Ascocarps fleshy, fleshy-waxy, thick or mem- 

 branous 

 Ascocarps fleshy-waxy, brittle when fresh, 



leathery when dry I. Sarcoscyphes. 



Ascocarps felty hairy externally 1. Sarcoscypha. 



Ascocarps covered with bristle-like hairs 



externally — 2. Pilocratera. 



Ascocarps naked 

 Ascocarps springing from a sclero- 



tium 3. Sclerotiiua, p. 136. 



Ascocarps not springing from a 

 sclerotium 

 Spores 1-celled 



Substratum green 4. Chlorosplenium, p. 144. 



Substratum uncolored 5. Ciboria. 



Spores at length 2 to 4:-celled .... 6. Rutsticemia. 

 Ascocarps waxy, thick, tough or mem- 

 branous 



Ascocarps externally hairy II. Tiichopezizee. 



Ascocarps resting on an extended 

 arachnoid mycehum 



Spores 1-celled 7. Eriopeziza. 



Spores becoming several-celled ... 8. Arachnopeziza. 

 Ascocarps without arachnoid my- 

 celium 



Spores globose 9. Lachnellula. 



Spores ellipsoid or elongate 



Disk surrounded by black hairs. 10. Desmazierella. 

 Disk smooth 

 Paraphyses obtuse at the apex 

 Walls of ascoma dehcate; 

 spores mostly 1-celled, 

 rarely 2-celled at ma- 

 turity 11. Dasyscypha, p. 144. 



Walls of ascoma thick; 

 spores 2-celled at ma- 

 turity 12. Lachnella, p. 145. 



