310 Mycologia 



celled spores which behave in precisely the same manner. Among 

 other rusts producing these bodies is that occurring on Acacias, 

 and that which occurs on a species of Agropyron, probably the 

 species scabrum. There a priori two ways accounting for these 

 pycnidia, either (i) they are parasites on the rust, or (2) they 

 are an integral part of the rust, and represent another spore form 

 of the rust." " These two-celled bodies have, as I have in several 

 occasions publicly remarked, no slight resemblance to the so- 

 called spermagonia of several species of Aecidium and this idea 

 has already been fruitful of considerable discussion. Do not the 

 various bodies that have in this connection been called sperma- 

 gonia and spermatia need a more careful examination than they 

 have yet received." 



Halsted 10 reports it on the uredo sorus of the asparagus rust 

 and " in some localities this parasite upon the asparagus rust has 

 been so abundant as to make it difficult to find a fully developed 

 rust spot free from Darluca." Sirrine 17 finds it spreads upon the 

 uredo stage of the asparagus rust. " During past summer (1900) 

 Darluca attacked the aecidial stage of the rust about June 10. We 

 have even found sori in which the uredospores were apparently 

 destroyed by Darluca while at the bottom of the sorus a layer of 

 evidently healthy winter spores would be found." He is of the 

 opinion " that Darluca attacks the spores of only the aecidial and 

 uredo stages and does not injure the vegetative portions." Clin- 

 ton 5 reports it on the aecia, uredinia and telia of the asparagus 

 rust and occurring on the carnation and blue grass rust. Pam- 

 mel and Hodson 13 consider it does much to prevent the ravages 

 of the asparagus rust and report it common in 1900 on corn rust. 



Darluca filum is frequently found on Kueneola obtusa in the 

 eastern states. I have studied also material growing on Coleo- 

 sporium delicatulum on Euthamia tenuifolium and on Dicaeoma 

 poculiforme on Phleum pratense. Ellis and Everhart list Darluca 

 arcuata on the andropogan rust which differs from D. filum by 

 having three celled spores. 



The parasite is easily recognized when found on the Uredinia 

 and telia sori. It appears to overrun the sori after developing 

 aggregate black pycnidia that appear as in a stroma. It ap- 

 parently checks spore formation and distribution. 



