THE FUNGI WHICH CAUSE PLANT DISEASE 529 



Pycnidia more or less clearly cleft length- 

 wise 



Pycnidia elongate or lanceolate 7. Leptostroma, p. 530. 



Pycnidia subcircular 8. Labrella, p. 530. 



Pycnidia in a stroma 



Stroma phyllogenous 9. Melasmia, p. 530. 



Stroma growing on animal hairs 10. Trichophila. 



Leptothyrium Kunze & Schweinitz (p. 528) 



Pycnidia superficial or erumpent, dimidiate, scutiform, mem- 

 brano-carbonous, black, coalescing or scattered, ostiole variable, 

 structure cellular; conidia ovoid-oblong to fusoid. 

 Some one hundred species. 



In part=Gnomonia and Gnomoniella. 



L. alneum (Lev.) Sacc. on alder=Gnomoniella 

 tubiformis. Seep. 274. FL362.-£to- 



L. pomi (M. & F.) SaCC."^' ^'' thyrium oxy- 



Forming minute superficial black spots ; pycnidia spores. After 

 differentiated in late winter, 25-100 /i; conidia el- ^"' 

 liptic, 12-14 X 2-3 fi. The mycelium of the spots breaks away 

 and probably functions as a reproductive body. 



The fungus is common in sterile form on pomaceous fruits but 

 the sporing stages are rarely f oimd. 



L. periclymeni Desm., L. aceiinum Ktz. and L. buzi Pass, are 

 on Lonicera, acer and box respectively. 



L. ozycocci Sh. "^ 



Pycnidia black, dimidiate, amphigenous, scattered, subco- 

 riaceous to coriaceous, irregularly subglobose, 

 subepidermal, erumpent, rupturing irregularly; 

 conidia subfusoid, sometimes slightly curved, 



^^^^^■' pseudoseptate, 10-15 x 2.5-3 /it; conidiophores 

 Fig. 363!^ el) to- simple, straight, tapering, slightly longer than 



thyrium oxycocet ^j^ conidla. 



Section of a pyc- "^ y^yj^^y^^- 



nidium, showing On cranberry. 



its dimidiate char- _ „ . t-. i . . j j. 



acter. After L. macrothecium Fcl. IS said to cause a 



^"" strawberry disease. 



L. peonse Br. & Cav. is on peony leaves. 

 L. parasiticum Poll, is on Cereus stems in Italy. 



