. BOTANICAL SUBJECTS. 73 



Although fusion of two or more capitula is so common in 

 many cultivated composites, I have been unable to trace this mode 

 of modification in wild composites. 



In Perth, along the road sides, where the large white 

 Marguerite (probably Chrysanthemum leucanthennum of Syme) 

 was very plentiful, I searched in vain for traces of fusion in the 

 capitula. Every flower was perfectly circular. 



Again, on an extensive lawn, which in winter is turned into a 

 skating pond, there was an immense number of another white 

 Marguerite (probably Chrysanthemum inodorum of Syme) . Among 

 these I also failed to find traces of duplicity. i!^or have I been 

 able to find traces of this mode of modification in the composites 

 grown in the herbaceous plot in the Eoyal Gardens at Kew. 

 Presumably most of them are wild species, although not under the 

 same unrestricted competitive conditions of composites growing in 

 a state of nature. 



It does not follow, however, that because one has not been able 

 to discover such modifications in a cursory inspection of wild and 

 semi- wild composites that, therefore, they never occur. The reason 

 may perhaps be starvation, from close competition with selfs, and 

 other plants. 



I have entered a little more fully into this point further on, but 

 must leave its further investigation for some future occasion. 



With regard to the cultivated Pyrethrum, which has given rise 

 to such a large number of fine varieties, it is not difiicult to 

 imagine its genesis from the wild P. frutescens, with a very small 

 disk and a small ray, through this process of fusion. Indeed, the 

 genesis of the wild P. frutescciis itself is not difiicult to imagine, 

 as resulting from a fusion of the still more diminutive capitula of 

 Achillea, more especially as there is one species of Pyrethrum 

 called AchilleeBfolium. The leaves of the cultivated Pyrethrum 

 seem nearer to those of some species of Achillea than to the 

 leaves of the wild P.frutesvens. 



Senecio Doiia is described by Mr. G. Nicholson as ha"ving " five 

 or six ray fiorets," but I have seen at the Royal Kew Gardens a 

 whole plant, the fiowers of which had either no ray fiorets, or 

 either one, or two, or three, or four, or five ligulate florets, where 

 the ray ought to be. Its character was irregularity of the ray 

 florets. One can easily imagine that the fusion of several of these 

 might in time produce the regular and larger heads, say of 



