THE FUNGI WHICH CAUSE PLANT DISEASE 189 



Perisporiacese (p. 170) 



■ Aerial mycelium covering the substratum with a dark growth, 

 rarely absent, usually astromate. Perithecia on the mycelial threads 

 or on a stroma, black, more or less globose, without opening or 

 appendages, although in some genera (Meliola, etc.) mycelial out- 

 growths from the base of the perithecium simulate appendages. 

 Asci elongate, numerous; spores various; paraphyses none. 



Chiefly parasites, although several genera are saprophytes. 

 About three hundred species. 



Aside from ascospores, in some species coriidia of one or several 

 forms are known. These may be borne in pycnidia or uncovered 

 on hyphae. Apiosporium is especially rich in the number of. its 

 conidial forms. 



Key to Genera of Perisporiacese 



Spores 1-celled 

 Spores not curved 



Spores hyaline 1. Anixia. 



Spores brownish 2. Orbicula. 



Spores curved, green 3. Pseudomeliola. 



Spores 2-celled 

 Spores, at least when inunature, ap- 



pendaged 4. Zopfiella. 



Spores not appendaged 

 Perithecia borne on the aerial mycelium 

 Spores not enlarging after maturity 

 Spores smooth 

 Aerial mycelium prominent. ... 5. Dinierosporium,p.l91. 

 Aerial mycelium none, or poorly 

 developed 

 Asci cylindric-clavate; para- 

 sites 6. Parodiella. 



Asci saccate, large; sapro- 

 phytes 7. Zopfia. 



Spores finely echinulate 8. Marchaliella. 



Spores enlarging after maturity ... 9. Richonia. 



Perithecia borne on a hairy stroma 10. Lasiobotrys, p. 191. 



Spores 3 or more celled 

 Aerial mycelium none or poorly developed 



