COLEOSPORIUM 323 
Teleutospores. Sori filling large intercellular spaces of the 
mesophyll towards the lower sur- 
face of the leaf; spores prismatic, 
length up to 140y, breadth 18— 
28 w; epispore 18—21 yw thick, or 
more, at the summit. 
Aicidia on (?both) leaves of 
Pinus silvestris; uredo- and teleu- 
tospores on Tussilago Farfara, 
May—November, very common. 
(Fig. 248.) 
The connection of the spore-forms 
on the alternate hosts has been demon- Frig.243. C. Tussilaginis. Mcidia 
strated by Plowright, Klebahn, Fischer > eee 
and Wagner. Klebahn and Fischer experiment), reduced; uredo- 
showed moreover that the parasite can- and young teleutospore x 600. 
not be transferred to Petasites or Sonchus. 
Plowright produced the ecidia (P. Plowrightiz) on leaves of Scots Pine 
from the Coleosporium on Tussilago (experiment 1248), 25th May, 1899. 
His specimens show the peridia, in almost every case, on both leaves of 
the fascicle. The same is true of the following experiment by Blackman : 
In October, 1904, he tied leaves of Coltsfoot bearing germinating teleuto- 
spores of C. Tussilaginis on four trees of P. silvestris at Crockham Hall, 
Kent. On April 14th, 1905, the beginnings of spermogones and ecidia 
were visible in three cases on neighbouring needles, but nowhere else. In 
June, 1905, all four showed the Peridermiwm. Specimens in Herb. Kew. 
The uredospores are often very densely and rather coarsely verruculose, 
but also occasionally smooth either wholly or in parts ; in fact the warts 
are deciduous and may disappear entirely. 
DISTRIBUTION: Europe. 
3. Coleosporium Petasitis Lév. 
Coleosporium Petasitis Lév. Ann. Sci. Nat. 1847, p. 373. Cooke, 
Handb. p. 521; Micr. Fung. p. 217. Fischer, Ured. Schweiz, 
p. 450. 
C. Sonchi Plowr. Ured. p. 250 p.p. Sace. Syll. vii. 752 p.p. 
Peridermium Boudiert Fischer, Contrib. étude du genre Coleosporium, 
in Bull. Soc. Bot. Fr. xli. 171. 
Aicidiospores. ABcidia (P. Boudiert) like those of neigh- 
bouring species. 
21—2 
