Shear: An Undescribed Ascomycete 



243 



tion ; and III a conidial stage. Where more than one conidial form 

 occurs in the life cycle of a species, as in the present case, this may- 

 be indicated by the use of an alphabetical exponent, as III a and 

 IIP, and the same may be used where more than one pycnidial 

 form occurs, thus in macro- and micro-pycnidia the former would 

 be II a and the latter IP. We have used I for the ascogenous* 

 stage, because of the rather uniform, present practice in pleo- 

 morphic species of describing this stage first. It should go without 

 saying that no idea of homology with the rusts is to be inferred 

 from the use of similar symbols. 



Fig. 3. Allescheria boydii. a, Dendrostilbella stage, X 277 ; b, conidiophore of 

 same with young conidia, X 530; c, conidia of same, X.530. 



Binomial names are suggested for the conidial forms of this 

 fungus, because in the present state of our knowledge of the 

 genetic relationships of the various form-genera, it seems necessary 

 to use separate binomials in referring to conidial and pycnidial 

 forms when found separate and there is doubt as to their ascog- 

 enous stage. When our knowledge of life cycles is as complete as 

 it is in the rusts, we should be able to discard form-genera and use 

 only the one binomial name and the symbols to indicate the differ- 

 ent spore forms. 



Bureau of Plant Industry, 

 Washington, D. C. 



