188 THE FUNGI WHICH CAUSE PLANT DISEASE 



or more or less persistent; perithecia usually scattered, rarely 

 gregarious, 140-270 /t, rarely up to 350 n; cells rather obscure, 

 15-20 fi; the apical outgrowth becomes mucilaginous attaching 

 the perithecium firmly to places where it may fall; appendages 



Fig. 137. — Phyllactinia corylea. 1. Natural size, on 

 chestnut leaf. 2. Perithecium enlarged. 3. Two asci. 

 4. Three spores. 5. Conidia-bearing hyphae. 6. Co- 

 nidium germinating. After Anderson. . 



5-18, equatorial, 1 to 3-times the diameter of the perithecium; 

 asci 5-45, subcylindric to ovate-oblong, 60-105 x 25-40 fi, more 

 or less stalked, 2, rarely 3-spored; spores 30-42 x 16-25 /t. 



Conidia (=Ovulariopsis) acrogenous, solitary, hyaline, sub- 

 clavate. 



On Magnolia, Liriodendron, Berberis, Xanthoxylum, Ilex, Celas- 

 trus, Acer, Desmodium, Crataegus, Heuchera, Ribes, Hamamelis, 

 Fraxinus, Asclepias, Catalpa, Cornus, Ulmus, Betula, Alnus, Cory- 

 lus, Ostrya, Carpinus, Quercus, Castanea, Fagus and Typha. 



