12 Raymond J. Pool 



late ; spores 2, rarely 3 or 4, variable in size, usually large, some- 

 times curved, 30-42 X 16-25/x,. 



On: Aralia nudicaulis, Celastrus scandens, Cornus stolonifcra, 

 Fraxinus lanccolata, Ostrya virginiana, Xanthoxylum 

 aincricauuiu. 



Ashland, Crete, Florence, Fort Niobrara, Gordon, Lincoln, Long 



Pine, Omaha, Saltillo, Wabash, Weeping Water, Valentine. 



This species is very readily recognized by the larger peri- 



thecia which are very commonly lens-shaped, with a fringe of 



clear appendages with inflated bases. 



Unci nu la Lev. 



Perithecia globose to globose-flattened ; asci several, 2-8- 

 spored ; appendages simple and free from the mycelium, recur- 

 ved or coiled at the tip. 



KEY TO THE SPECIES 



I. Appendages colored for more than half their length. 



1. Asci 4-6, 4-7-spored, appendages variable, 6-35.. U. necator 

 TT. Appendages colorless for their whole length. 



2. Asci 8-20, 2-spored, appendages 50-125 U. macros pora 



3. Asci 8-15, 4-6-spored, appendages 100-150 U. salicis 



4. Asci 10-26, 7-8-spored, appendages densely crowded, 



U. circinata 



Uncinula necator (Schwein.) Burrill 



Erysiphe necator Schwein. 

 Uncinula spiralis B. & C. 

 Uncinula anipclopsidis Peck. 



Amphigenous ; mycelium sub-persistent, thin and effused, or 

 forming circumscribed patches, sometimes evanescent; perithe- 

 cia usually epiphyllous or sometimes hypophyllous as well, oc- 

 casionally on the inflorescence of the host, globose-depressed, 

 more or less scattered, 70-128^. in diameter, averaging 98^, cells 

 distinct, irregular in shape, io-20/t wide; appendages very variable 

 in number and length, 6-35, one to four times the diameter of the 

 perithecium, smooth, simple, septate, thin-walled, light or dark 

 brown in the lower half, tip helicoid when mature; asci 4-6, 

 ovate or ovate-oblong to sub-globose 50-60 X 30-40/*. ; spores 



4-7, 18-25 X 10-12/*. 



On: Parthcnocissus quinqucfolia, litis cordifolia, V. riparia, 

 V. sps. 



70 



