526 THE FUNGI WHICH CAUSE PLANT DISEASE 



Cytosporina Saccardo (p. 518) 



Stroma valsoid, cushion-formed or tubercular; pycnidia sunken, 

 the ostiole erumpent; conidia filiform, curved, 1 -celled. 



Twenty species of bark and wood inhabiting fungi. 



These are, in part at least, conidial forms of the Valsaceae. 



C. ribis Miy.^'^ occurs on currant and gooseberry bushes in 

 Holland attacking the cortex, later the wood, and killing the 

 shoots. 



Nectrioidaces (p. 479) 



Pycnidia fleshy or waxy, light colored, globose, rarely cup- 

 shaped or hysterioid; stroma present or absent; conidia various, 

 usually hyaline. 



This group contains some twenty-five genera none of which are 

 serious plant pathogens. Some are conidial forms of the ascigerous 

 fungi Aschersonia and Polystigma. 



Ket to Subfamilies and Groups of Nectrioidacee 



Pycnidia globose, ostiolate I. Zythiese. 



Conidia l-ceUed 



Hyaline 1. Hyalospors, p. 526. 



Dark colored 2. Phseospors. 



Conidia two-celled hyaline 3. Hyalodidymia. 



Conidia 3 to several-celled, hyaline 



Elliptic to fusoid 4. Hyalophragmiae. 



Bacillar to filiform 5. Scolecospora. 



Pycnidia cupulate or hysterioid II. Ollules. 



Zythies-Hyalospors 

 Conidia hyaline, continuous, ovoid to elliptic. 



Ket to Genera of Zythiacee-Hyalospore 



Pycnidia separate 

 Pycnidia smooth 

 Pycnidia beakless 

 Conidia in chains 1. Sirozythia. 



