JJ2 NATURAL HISTORY BULLETIN. 



The fungus attacking the fertile catkins of Popuhis species 

 had recently been published as Taphrina rhizopJwra Johanson. 

 After very careful study of its description in Sadebeck's pub- 

 lications and the original one of Johanson, together with com- 

 parison of mv microscopic preparations with their plates. I 

 feel justified in adopting the above classification, and in 

 expressing a doubt if the genuine Taphrina rhizophora occurs 

 in America, 



Wishing authoritative advice, I sent some diseased catkins 

 of Popnius trcmnloides to Prof. Sadebeck; he very kindl}- 

 replied, giving the classification as lierewith presented, to- 

 gether with material for comparison. The parasite causes 

 hvpertrophy of the carpels, which become about double their 

 normal size, and when the asci are mature appear covered 

 bv a yellow frost. In shape the asci are more or less clavate, 

 and generally rounded at the top. 



They are 14-20" in width of the part that is above the epi- 

 dermis, in length 46-105/^; the narrower portion penetrates 

 between the epidermal cells and even a short distance below: 

 it is very irregular in shape, and in width about 8//. The asci 

 are remarkable for their golden-yellow contents, and in that 

 respect resemble Taphrina aurca ( Persoon ) Fries on Popii- 

 Itis leaves. The spores are 4« in diameter, and have man}- 

 conidial formations. x\ brief outline of the microscopical feat- 

 ures of Taphrina rhizophora Johanson may serve to indicate 

 the lack of resemblance of the species under discussion. The 

 asci of Taphrina rhizophora are the largest of all. being 120- 

 i6o,« in length: an immersed portion of 40-80/i extends into 

 the interstices between the cells of the host even to the third 

 or fourth row, and this portion may be divided into two pro- 

 cesses. Such extreme length of asci, their deep penetration 

 and division into processes I have in no instance found in 

 American material. I have examined Popnius trcmnloides, 

 collected at Medford. Mass.. by Mr. A. B. Seymour, the 

 material from Newfield. N. J., distributed as N. A. F. No. 

 1885 and the same host sent me from Racine, Wis., by Dr. 

 J.J. Davis: the Popnlns o-ra)ididcntata specimens were from 



