20 INTRODUCTION. 



range of variation in these plants. Unfortunately onr 

 information on this subject is rarely siifi&cient to give con- 

 fidence to our determinations. The recorded geographical 

 distribution of a species is often far from telling the whole 

 truth : it may seem to show that a plant is confined to a single 

 spot, or nearly so, and thus cause just doubts concerning its 

 being a distinct species; whereas, in reality, it is so abun- 

 dant in that place, and under such various circumstances, 

 that its claim to be considered as a distinct species may ba 

 held to be well founded. For instance, R. pyramidalis seems, 

 by the geographical table, to have been found in three or 

 four localities, separated by long distances, and would pro- 

 bably have been considered as a doubtful species, had not 

 its extreme abundance in the valley of Llanberis attracte-l 

 especial attention to it, and shown that its limits of varia- 

 tion are narrow, and that it presents a clearly distinct ap- 

 pearance (facies), and also admits of an accurate definition. 



Some botanists have ventured to state that the seeds of 

 Brambles do not readily germinate, that therefore we sel- 

 dom see a seedling, and that thickets of these plants are 

 almost wholly derived from the rooted ends of the stems. 

 Careful observation has proved to me that the exact oppo- 

 site is the fact, that the seeds germinate freely, and that 

 seedlings are easily found in abundance by those who search 

 for them in the proper places. 



Mr H. C. Watson informs me that Brambles are sown 

 by the birds in his grounds at Thames Ditton, and that 

 abundant seedlings appear, and have to be carefully re- 

 moved ; and that that is also the case in his hedges, which 

 he has known from the time of their being planted more 

 than thirty years since. During the whole of that time 



