62 GROWTH OF THE 'ORIGIN.' 



line of Siberia. Perhaps Siberia more concerns the northern 

 Flora of North America. The ranges of the plants to the 

 east and west, viz. whether most found are in Greenland and 

 Western Europe, or in E. Asia, appears to me a very interest- 

 ing point as tending to show whether the migration has been 

 eastward or westward. Pray believe me that I am most 

 entirely conscious that the only use of these remarks is to 

 show a botanist what points a non-botanist is curious to 

 learn ; for I think every one who studies profoundly a subject 

 often becomes unaware [on] what points the ignorant require 

 information. I am so very glad that you think of drawing up 

 some notice on your geographical distribution, for the area 

 of the Manual strikes me as in some points better adapted 

 for comparison with Europe than that of the whole of North 

 America. You ask me to state definitely some of the points 

 on which I much wish for information ; but I really hardly 

 can, for they are so vague ; and I rather wish to see what 

 results will come out from comparisons, than have as yet 

 defined objects. I presume that, like other botanists, you 

 would give, for your area, the proportion (leaving out intro- 

 duced plants) to the whole of the great leading families : this 

 is one point I had intended (and, indeed, have done roughly) 

 to tabulate from your book, but of course I could have done 

 it only very imperfectly. I should also, of course, have ascer- 

 tained the proportion, to the whole Flora, of the European 

 plants (leaving out introduced) and of the separate great 

 families, in order to speculate on means of transportal. By 

 the way, I ventured to send a few days ago a copy of the 

 Gardeners* Chronicle with a short report by me of some 

 trifling experiments which I have been trying on the power 

 of seeds to withstand sea water. I do not know whether 

 it has struck you, but it has me, that it would be advisable 

 for botanists to give in whole numbers, as well as in the 

 lowest fraction, the proportional numbers of the families, thus 

 I make out from your Manual that of the indigenous plants 



