10 32 Proceedings of the Royal Irish Academy. 



Trail/ BurkihY and Dewey, 3 treating of certain interesting phases of this 

 modern feature in our flora, will be found instructive. Scott Elliot 4 and 

 Miall 5 have written good chapters on the general subject; Hooker 6 has 

 discussed the introduction and spreading of Compositae; aliens in central 

 London have recently excited some interest 7 ; and as regards Ireland, some 

 information will be found in certain writings by Adams, 8 Miss Knowles, 9 and 

 myself. 10 



The influence of man upon the vegetation of the earth has been so 

 profound, and so different both in degree and in kind from that exercised 

 by the rest of the animal kingdom, that it is customary and useful to 

 distinguish between them ; we say that seeds brought by a bird in mud 

 for building its nest are brought by " natural " means, while seeds brought 

 by man in mud to build his hovel are brought by " artificial " means. 

 It is curious to speculate at what particular period man became the author 

 of "artificial" actions. Presumably Pithecanthropus was guilty of no 

 " introductions " ; nor could the seeds carried and dropped when man 



"bruised the herb and crush'd the grape, 

 And bask'd and batten'd in the woods," 



be classed differently from those scattered by the birds. But when man 

 began to subject first the wild animals and then the woods to his will, 

 his influence on nature became so profound as to justify us in placing it 

 in a separate category. It is true that Woodruffe-Peacock pleads 11 for what 

 he considers a broader and more natural treatment of the subject, by including 

 man and all his works among the " natural " phenomena, and placing his 

 influence on the same footing as that of the wild beasts and birds. Certainly, 

 one wishes this could be done ; but it would only lead to confusion, especially 

 in the domain of geographical botany. The results of man's work have been 

 so rapid and revolutionary, so completely destructive of the gradual influences 



1 J. W. H. Tbail : Florida of a piece of waste ground near Aberdeen. Ann. Scott. Nat. Hist., 

 v., pp. 231-235 ; vi., 24-31, 237-245; viii., 221-230. 1896-9. 



2 1. H. Bvrkixl : Notes on the Plants distributed by the Cambridge dust-carts. Proc. Cambridge 

 Phil. Soc, viii., pp. 92-95. 1895. 



3 L. H. Dewey : Migration of Weeds. Yearbook U.S. Dept. of Agriculture, 1896, pp. 263-286. 



I G. F. Scott Elliot : Nature Studies (Plant Life), chap, xxvii. 1903. 



5 L. C. Miall: Round the Year, pp. 200-208. 1899. 



6 Notes on the Classification, History, and Geographical Distribution of the Compositae. Journ. 

 Linn. Soc. (Botany), xiii., pp. 568-577. 1873. 



7 Wild Flowers in the Strand. Journ. of Horticulture, lv, p. 122. 1907. 



8 J. Adams : On the possibility of distinguishing between native and alien species of plants in 

 Ireland. Irish Nat., xviii., pp. 123-132. 1909. 



9 M. C. Knowles: A contribution towards the alien flora of Ireland. Irish Nat., xv., 

 pp. 143-150. 1906. 



10 Knowledge, xxv., pp. 16-19, 1902, and Irish Topographical Botany, pp. xxxiv-xxxviii. 1901. 



II E. A. Woodkufee-Peacoce : Natives and Aliens. Journ. Bot.. xlvi., pp. 390-396. 1908. 



