THE FLORA OP PLYMOUTH. 



17 



THE FLOEA OF PLYMOUTH: 



ITS DENIZENS, COLONISTS, AND ALIENS. 



ABSTRACT OF MR. ARCHER BRIGGS'S PAPER. 



This Lecture may be considered as an attempt towards supplying 

 an answer to such a query as the following : "Which plants of the 

 existing Flora of Plymouth must we reject when questions relating 

 solely to aboriginal species are under our consideration ? 



The lecturer commenced by observing that a thoughtful student 

 of nature often finds mysteries where a superficial or careless 

 observer would suppose that there were none. The Phyto - geogra- 

 pher — who studies the distribution of plants over the earth's sur- 

 face, examines and enquires into their respective distribution — 

 has, however, to confess that his science, like that of the geologist, 

 has problems which he cannot solve ; that why this plant is herej 

 that there, is sometimes a mystery, as differences of surface, soil, 

 and climate, three most powerful influences in controlling vege- 

 tation, do not always supply a reason. Moreover, in some quarters 

 of the world he has to encounter the difficulty of having to duly 

 estimate the extent to which man's influence has gone to control 

 the range of certain species. He sees the lord of creation, especially 

 when in a civilized state, selecting and propagating such plants as 

 he finds necessary to his well-being, either from their furnishing 

 food for himself or for the domestic animals with which he sur- 

 rounds his dwelling: cherishing, indeed, all those species that in 

 any way contribute to his enjoyments or his pleasures. The 

 productions of his own country are not sufficient to satisfy his 

 desires ; for, when there are not insurmountable obstacles, he, to 

 satisfy them, transports certain species from one part of the world 

 to another. Then, to carry out his plans the more fully, it becomes 

 his [dm to reduce in number, or even extirpate, such others as 

 would interfere with the growth or due development of the fa- 

 voured ones. Nor is it only directly that he exercises an influence 

 on the vegetation of the world ; but indirectly, and often uncon- 

 sciously, he has done, and is still doing, much to control or alter 

 the range of certain plants. The words Denizens, Colonists, and 

 Aliens entering as they do into the title of this paper, suggested 



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