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Gray, Asa in correspondent 
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From:
Asa Gray
To:
Charles Robert Darwin
Date:
1 June 1857
Source of text:
DAR 8: 47bA
Summary:

Comments on species with disjoined ranges; does not feel, despite CD’s expectations, that they tend to belong to small families.

Gives the proportion of U. S. trees in which the sexes are separate [see Natural selection, p. 62].

Contributor:
Darwin Correspondence Project
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From:
Charles Robert Darwin
To:
Asa Gray
Date:
18 June [1857]
Source of text:
Archives of the Gray Herbarium, Harvard University (9a)
Summary:

Thanks for AG’s remarks on disjoined species. CD’s notions are based on belief that disjoined species have suffered much extinction, which is the common cause of small genera and disjoined ranges.

Discusses out-crossing in plants.

Has failed to meet with a detailed account of regular and normal impregnation in the bud. Podostemon, Subularia, and underwater Leguminosae are the strongest cases against him.

Contributor:
Darwin Correspondence Project