464 PUCCINIA ON GROUNDSEL, 



and the common Groundsel is likely to have some well-known 

 rust upon it. Groundsel is an imported weed, probably from 

 Britain, and j&t curiously enough the very common Groundsel 

 rust of the old countr}^ (Coleosporium senecionis, Fries) has not 

 yet been met with here. 



In Plowright's " Monograph of the British Uredinese and 

 Ustilaginese " the following three Puccinias are given as occurring 

 on species of Senecio, but none of them on S. vulgaris — 



P. qlomerata, Grev., (thought to be the typicalP. expansa, Link). 

 P. senecionis, Lib. 

 P. schoeleriana, Plow. &. Mag. 

 The two former belong to the Micropncciiria or those which 

 have teleutospores only, and the latter to the HpAero-p'iccinia, in 

 wdiich there are the three kinds of spores, the aecidiospores being 

 on one host-plant and the uredospores and teleutospores on a 

 different host-plant. Assuming that the complete life-histor}^ of 

 the above species is known, our fungus belongs to a different 

 group, but on the Continent of Europe P. senecionis is known to 

 produce aecidiospores as well,"^ and therefore it might l^e a similar 

 species to ours. But the sori are brown, not black, and that 

 excludes it, while on- P. g i orufivata the teleutosj^ores are too small 

 for the present species, and the colourless papilla surmounting the 

 upper cell is absent from ours. So that there appears to be no 

 corresponding fungus on British species of Senecio. 



Turning now to Farlow and Seymour's " Host-Index of the 

 Fungi of the United States," the following are given on species of 

 Senecio there, and here again S. vulgaris has only the common 

 British rust already mentioned : — 



Afcifiium compositai'um, Mart, 

 A. senecionis, Desm. 

 /'uccin.ia conglomerata, Schm. ct Kze. 

 The Puccinias (for there are several) of which A. compositarum 

 is regarded as a stage, belong for the most part to the Hefero- 



* See Dietel ia Zeitsch. f. Pflanzenk. Vol. iii. Pt. 5, 259 (1893). 



