LIFE-HISTORY OF ZXCIDIUM ON PARIS QUADRIFOLIA. 43 
On the Life-history of the AScidium on Paris quadrifolia. By 
Cuares B. Prowrteut, M.D., and W. Taomson. (Com- 
municated by the President.) 
[Read 16th February, 1893.] 
Puccrnia Parrpis. 
Tue Acidium on Paris guadrifolia is a very rare fungus in 
Great Britain, having so far only been recorded as occurring 
near Carlisle, where it appears in but small quantity. It was 
first found in May 1890 by Mr. W. Thomson, who has this year 
cooperated with me in working out its life-history. After con- 
siderable difficulty, we have succeeded in demonstrating that it 
is connected with a Puccinia on Phalaris arundinacea. This last- 
named plant has already been shown to be the host of no less 
than four species of Puecinia whose ecidial host-plants are not 
interchangeable, viz. :— 
Puceinia sessilis on Allium ursinum. 
” Phalaridis ,, Arum maculatum. 
” Digraphidis ,, Convallaria majalis. 
” coronata »,  BRhamnus Frangula. 
Dr. H. Klebahn, of Bremen, further finds that it harbours a 
Puceinia whose ecidiospores occur on Convallaria Polygonatum ; 
but whether this be specifically distinct from P. Digraphidis has 
not yet been ascertained. 
The teleutospores of P. Paridis germinated in April ; but when 
applied to Arum maculatum, Allium ursinum, and Convallaria 
majalis, produced no result. When placed upon the foliage of 
Paris quadrifolia, however, in two separate cultures, each of 
which included more than one plant, they gave rise to the ecidium. 
Control plants of Paris quadrifolia remained healthy. 
It is very remarkable that Phalaris arundinacea should be the 
host of so many Puccini: it is a widely distributed plant, but 
some of the host-plants of the various ecidiospores are very local 
in this country. It would seem as if these Puccint@ were the 
survivors from a period when their respective scidial host-plants 
were far more abundant than is the case at the present time. 
Appended are the results of our cultures in a tabular form. 
