186 FUNGI. 



graminis) which succeeded it. The simple spored rust first 

 makes its appearance, and later the bilocular " mildew." It is 

 by no means uncommon to find the two forms in the same pus- 

 tule. Some have held, without good reason, that the simple 

 cells became afterwards divided and converted into Puccinia, 

 bat this is not the case ; the uredo-spores are always simple, and 

 remain so except in Uredo linearis, where every intermediate 

 stage has been observed. Both are also perfect in their bind,^ 

 and capable of germination. 



What the precise relations between the two forms may be has 

 as yet never been revealed to observers, but that the two forms 

 belong to one species is not now doubted. Very many species 

 of Puccinia have already been found associated with a corre- 

 sponding Trichobasis, and of Phragmidium with a relative Lecy- 

 thea, but it may be open to grave doubt whether some of the 

 very many species associated by authors are not so classed upon 

 suspicion rather than observation. We are ready to admit that 

 the evidence is strong in favour of the dimorphism of a large 

 number of species — it may be in all, but this awaits proof, or 

 substantial presumption on good grounds. Up to the present we 

 know that there are species of Trichobasis which have never 

 been traced to association with a Puccinia, and doubtless there 

 will be species of Puccinia for which no corresponding TJredo 

 or Trichobasis can be found. 



Tulasne remarks, in reference to Puccinia sonchi, in one of his 

 memoirs, that this curious species exhibits, in effect, that a Puc- 

 cinia may unite three sorts of reproductive bodies, which, taking 

 part, constitute for the mycologists of the day three entirely dif- 

 ferent plants — a Trichobasis, a Uromyces, and a Puccinia. The 

 TTredines are not less rich, he adds, in reproductive bodies of 

 divers sorts than the Pyrenomycefes and the Discomycetes ; and 

 we should not be surprised at this, since it seems to be a law, 

 almost constant in the general harmony of nature, that the 

 smaller the organized beings are, the more their races aro 

 prolific. 



In Puccinia variabilis, Grev., it is common to find a unicellular 

 form, species of Trichobasis, in the same pustules. A like circum- 



