COLEOSPORIUM 321 
ficidia on (?one of the two) leaves of Pinus austriaca, 
P. silvestris, May, June; uredo- and teleutospores on Senecio 
Jacobaea, S. palustris, S. silvaticus, S. viscosus, S. vulgaris, all 
through the year; also recorded for S. pulcher, S. sarracenicus, 
etc, in Botanic gardens, and on cultivated Cinerarias (ie. 
Senecio) at Sydenham; see Journ. Roy. Hort. Soc. 1908, xxxiil. 
511. Very common. (Figs. 241, 242.) 
Fig. 241. C. Senecionis. a, chain Fig. 242, C. Senecionis. Teleuto- 
of uredospores; b, two fascicles spore germinating. 
of leaves of P. silvestris, bearing 
peridia on one leaf only of each 
fascicle (reduced). 
This is the species of Coleosporiwm whose life-history has been longest 
known; Wolff first experimentally demonstrated it in 1872, and he was 
followed by Plowright in 1882, as well as by Cornu, Hartig, Rathay, Von 
Thiimen, Rostrup, Klebahn and Fischer. The ecidium had previously 
been called Peridermium. Since Senecio vulgaris continues to live through 
the winter in our climate, and Magnus and others have found the uredo- 
spores throughout the year, the intervention of the alternate host is 
not in this case necessary. Yet it is generally quite easy to find the 
Peridermium on the needles of P. silvestris if one searches in June any 
trees that may be growing in the neighbourhood of Groundsel infected 
with the parasite; since the Peridermium is not conspicuous, it may easily 
be overlooked unless special search is made. It is probable that there are 
several biological races of this fungus, on different species of Senecio, and 
it has been proved by Fischer that it cannot be transferred to Cacalia or 
Sonchus. 
GU. 2] 
