232 Scientific Intelligence. 



this group, ventures " to believe that under Miitisiacece are in- 

 cluded very many different lines of descent, but that among them 

 there are some minor groups distinguished by very high relative 

 antiquity." And in another connection he opines " that the argu- 

 ments that have led some distinguished botanists to consider the 

 great family of Composite as of comparatively recent origin to 

 appear to me altogether inconclusive. When I consider the vast va- 

 riety of forms which it includes, the degree in which some large 

 groups are localized in different regions of the earth, while Others, 

 such as Se?iecio, have representatives in every zone, I shrink 

 from the conclusion that their origin can be, even in geological 

 language, at all recent. It is, of course, not inconceivable that 

 plants which we class together under the name Composites may 

 have come into existence by different lines of descent through 

 gradual modification from different ancestral types. But, when 

 we consider the general agreement in the structure and arrange- 

 ment of the essential organs, I think that the balance of proba- 

 bility inclines decidedly towards the belief in a community of 

 origin of all the various existing forms. Be that as it may, we 

 are, I think, justified in looking to the mountain region of South 

 America as the original home of many large groups, such as the 

 genus Baccharis, most of the Miitisiacece, and many genera of 

 other tribes." 



As to these two suggestions, although it is practically conven- 

 ient, and perhaps necessary, to bring all the Labiatifiorous Com- 

 posites under one tribe, as Bentham has done, it seems to us alto- 

 gether probable that the existing forms are descended from different 

 lines of ancestry. Indeed by such a conception we can more 

 naturally understand their diverse affinities. But as to the great 

 order they belong to, if there is any large group in which the 

 structure suggests community of origin, it is the Composites. 

 And we suppose that systematic botanists of large experience 

 would entirely agree with Mr. Ball, that the wide differentiation 

 and distribution of this vast order indicated its high antiquity. 

 Our author has assigned some strong reasons for this opinion. 

 The only argument to the contrary, that we know of, is an ideal 

 one, based upon two suppositions ; one, that Dicotyledons culmi- 

 nate in the Composites and in such-like orders ; the other that the 

 highest ideal type of plants must be of the latest evolution. But, 

 indeed, the vegetable commonwealth shows no tendency to cul- 

 minate in any one group or set of groups ; and it is a question- 

 able morphology which would promote the capitulum of a thistle 

 or a dandelion to the head of the class. 



We remember an interesting lecture, in which, recognizing 

 the dominant part which the northern hemisphere and its 

 boreal lands, with their favorable configuration, have undoubt- 

 edly played in floral distribution, it was inferred that the 

 role of the southern had always been comparatively insignifi- 

 cant. But a great deal may have happened in the austral 

 regions before this boreal supremacy was established. Mr. Ball 



