To Asa Gray 11 August [1858]
Summary
Species migration since the Pliocene. Effect of the glacial epoch. Present geographical distribution, especially similarities of mountain floras, explained by such migration; mountain summits as remnants of a once continuous flora and fauna.
Cross-fertilisation in Fumariaceae.
| Author: | Charles Robert Darwin |
| Addressee: | Asa Gray |
| Date: | 11 Aug [1858] |
| Classmark: | Archives of the Gray Herbarium, Harvard University (42 and 9a) |
| Letter no: | DCP-LETT-2321 |
