152 ASCOJIYCKTES. 



The E.coasccac may be groupetl, according to the symptoms 

 of the disease produced, as follows ; for this purpose we shall 

 class all the species as one genus, ' Exoaseus' (or Taphriva): 



I. Species which cause deformation of the ovary or other part 

 of tlie fruit. 



E. pritni (Fuclc.) on I'nnii/.s dumcsfica, 1\ Padui^, 1\ vir- 



giniana. 

 E. RostrupianKti (vSad.) on Primus spinosa. 

 E. communis (Sad.) on Pnmus 2')umilla, P. maritima, P. 



nigra, P. americana. 

 E. Farlowii (Sad.) {E. varius, Atk.) on Prunus scrotiiia, 



causing also deformation of twigs. 

 E. longipes (Atk.) on Prunus americana. 

 E. confusus (Atk.) on Prunus virginiana. 

 E. o^hizipes (Atk.) on Prunus trifiora. 

 E. cecidomophilus (Atk.) on insect-galls on the fruits of 



Prunus virginiana. 

 E. mirabilis (Atk.) on Prunus angvstifoiia, 1\ liortulana, 



P. americana. 

 [Also species on Prunus suhcordata, P. Chicasa, and P. 



pennsylvanica.'] 

 E. alni incan/ie (Kiihn) (E. amcnt.orvrn, Sad.) on Alnus 



incana. 

 E. alni glutinosae (Tubeufj on Alnus glutinosa. 

 E. Robinsonianus (Giesh.) on Alnus incana. 

 E. Johansonii (Sad.) on Populus trnnula, /'. h'cnudoidfs, ]\ 



grandidentafa. 

 E. rhizojylwrus (Johan.) on Populus (dha. 



II. Species whicli (1) produce witches' brooms, or (2) at least 

 cause deformation of shoots ; asci produced on the leaves. 



(1) E. cpiphyllus (Sad.) {E. horcalis, Johan.) on Alnus 



incana (uniform grey coating of asci on l)oth sides 



of leaf.) 

 E. turgidus (Sad.) on Bdula verrucosa (coating of asci on 



under surface accompanied by slight crumpling of 



leaf). 

 E. hetidinus (Kostr.) on Bctula pudtesccns and B. odorata 



(coating of asci on under surface). 



