THE FUNGI WHICH CAUSE PLANT DISEASE 281 



stromata, beak exserted; asci 60-72 x 7-8 n; paraphyses slender, 

 septate, wavy; ascospores subelliptic, hyaline, continuous, 11-15 x 

 4-6 n. Fig. 210. 



The conidial stage was described by Reddick as the cause of 

 necrosis of grape vines '^* though he has since stated that the 

 amount of damage due to this disease is not so great as at first 

 thought. 



The ascigerous form in- pure culture in the hands of Shear '^^ 

 gave rise to the typical conidial form, identical with that grown 

 from pure cultiures of the pycnospores. 



Melanconis Tulasne (p. 279) 



Stroma valsoid, seated in the substratimi, partially erumpent; 

 perithecia clavate, immersed, with long cylindric beak; asci cylin- 

 dric, long-clavate, 8-spored; spores ellipsoid to elongate, hyaline. 



About twenty species; chiefly saprophytes. 



M. modonia Tul. in its conidial form (=Fusicoccum pernicio- 

 sum) causes a serious disease of the chestnut in Europe.^^' *''* 



Pseudovalsa longipes (Tul.) Sacc. is parasitic on oak. 



Diatrypaceae (p. 223) 



Stroma effused or pulvinate, built of thick hj^hse, under the 

 peridium, at length erumpent, bearing both asci and conidia or 

 present only with the conidia; perithecia sunken in the stroma or 

 superficial, ostiolate; asci usually thickened apically; 4 to 8 or 

 many-spored; spores usually continuous, small, cylindric, curved. 



About one hundred seventy-five species. 



One parasitic genus occurs on cherry and plum. 



Key to Tribes and Geneea op Diatrypacese 



Stroma absent from ascosporic stage I. Calosphaeriee- 



Asci 8 (rarely 4)-spored 



Spores 1-celled 1- Calosphseria, p. 282. 



Spores 2-ceUed 2. Cacosphaeria. 



Asci many-spored 3. Coronophora. 



Stroma present in the ascosporic stage II. Diatrypese. 



