ON COMPOSITE 



129 



This genus occupies an intermediate position between 

 , Uromyces and the less advanced genera, Phragmidiurn, etc., as 

 is shown by the fact that many species tend to form one-celled 

 teleutospores (mesospores) indistinguishable from those of 

 Uromyces, while others have spores with three or more cells, 

 arranged as in Phragmidiurn, Triphragmium, Sphaerophrag- 

 iii i a m, etc. 



The number of species is enormous, more than 1300 are 

 already known. The genus must therefore be subdivided, but 

 no quite satisfactory classification has as yet been discovered. 

 Schroter's and Fischer's separate nearly allied species, while 

 Arthur's is a pathless chaos. As a temporary measure, instead 

 of adding a new imperfect scheme to those already existing, 

 the species are here arranged on the plan adopted in Sydows' 

 Monographia, in the order of the families and genera on which 

 they are parasitic ; this has the advantage that it does, to a 

 great extent, bring nearly allied species 

 close together, while it is at the same time 

 very convenient for consultation. In each 

 family the genera are arranged in the order 

 familiar to British botanists, but the fami- 

 lies themselves are in the order usually 

 adopted on the continent, because that 

 will before long be accepted here also. 



1. Puccinia Tripolii Wallr. 



Puccinia Tripolii Wallr. Fl. Crypt. Germ. ii. 



223. Cooke, Micr. Fung. p. 207; Gre- 



villea, iii. 180. 

 P. Asteris Duby, Bot. Gall. ii. 888. Plowr. 



Grevillea, ii. 48 ; Ured. p. 215. Sacc. 



Syll. vii. (587 p.p. Sydow, Monogr. i. 

 15 Fig. 80. P. Tripolii. 



Teleutospores (one 



Teleutospores. Sori amphigenous, con- abnormal), 

 fluent into rather large, pulvinate masses, hard, compact, very 

 dark-brown ; spores oblong-clavate or clavate, rounded above or 

 somewhat narrowed and much thickened (as much as 8/f), 

 slightly constricted, generally attenuated downwards, smooth,, 



g. u. 9 



