Darwin-Hooker Letters : Letter from Darwin, C. R. to Hooker, J. D. on 12 Apr 1857 : 1r
'Darwin, C. R.'
Thanks Hooker for response on variation. Studying variations that seem correlated with environment, e.g., north vs south, ascending mountains. Darwin's weed garden: observations on slugs killing seedlings. Seed-salting. One-seventh of the plants of any country could be transported 924 miles by sea and would germinate.