ASEXUAL REPRODUCTION 



181 



ployed 2 families: Nectriaceae, having solitary perithecia, and 

 Hvpocreaceae, having perithecia seated within a stroma and there- 

 fore partially or wholly immersed. In some instances, as in the 

 Genus Nectria, the stroma is so meager as to invest only the basal 



E 



Fig. 69. Nectria and associated conidial stages. A. Nectria coccinea, habit 



sketch. B. Sporodochium (diagrammatic) of Tiibercularia vulgaris, in 



vertical section. C. Conidiophores and conidia of T. vulgaris. D. Conidia 



of Cylindrocarpon. E. Ascus and ascospores of Nectria coccinea. 



portion of the perithecia, whereas other species have completely 

 discrete perithecia. Septation of ascospores provides a workable, 

 although \\holly artificial, basis of generic classification. 



Asexual reproduction. Many of the Hypocreales possess 

 conidial or chlamydospore stages. The conidial stage of Nectria 

 cinnabarina on currants, pear, basswood, maple, elm, and oak is 

 Tiibercularia vulgaris. Nectria coccinea on beech [Ehrlich 

 (1934)] has a macroconidial stage belonging to the Genus Cylin- 

 drocarpon. Other species of Nectria, including N. ipoinoeae on 



