164 THE FUNGI WHICH CAUSE PLANT DISEASE 



Spores brown, elongate, 4 to 



8-celled 9- Hysterium. 



Spores elongate, muriform 10. Hysterographium, p. 164. 



Ascoma boat or band-shaped, not sessile 

 Spores spindle-formed, brown, many- 

 celled 

 Spores 4 to 8-celled ; asci 8-spored . 11. Mytilidimn. 

 Spores many-celled; asci 4-spored. 12. Ostreion. 

 Spores filamentose, hyaline or yellow 13. Lophium. 

 Ascoma stellate 14. Actidium. 



Hysterographium Corda 



Asci clavate, 8-spored; spores muriform, dark colored when 

 mature; paraphyses branched forming an epithecium. About 

 seventy species. 



H. frazini (Pers.) de Not. occurs on Oleaceae, particularly on 



Fig. 117. — H. 

 fraxini. Ascus 

 and paraphyses. 

 After Relim. 



FiQ. 118. — Gynmoaseus, sexual organs. 

 After Dale. 



the ash, perhaps only as a saprophyte, 

 and America. 



It is foimd both in Europe 



Aspergillales (p. 124) 



The Aspergillales are clearly distinguished from the other 

 Ascomycetes by the possession of a closed ascocarp in which the 

 asci are not collected in a hymenium but are irregularly scattered. 

 The forms with the least developed peridium are evidently related 



