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].
Showing 21–37 of 37 items
The Charles Darwin Collection
The Darwin Correspondence Project is publishing letters written by and to the naturalist Charles Darwin (1809–1882). Complete transcripts of letters are being made available through the Project’s website (www.darwinproject.ac.uk) after publication in the ongoing print edition of The Correspondence of Charles Darwin (Cambridge University Press 1985–). Metadata and summaries of all known letters (c. 15,000) appear in Ɛpsilon, and the full texts of available letters can also be searched, with links to the full texts.
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].
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.
Believes, with CD, that extinction may be an important factor in explaining plant distributions, but sees no reason why the several species of a genus must ever have had a common or continuous area. "Convince me of that, or show me any good grounds for it … and I think you would carry me a good way with you". It is just such people as AG that CD has to satisfy and convince.
Feels that the crossing of individuals is important in repressing variation and perhaps in perpetuating the species, but instances some plants in which it cannot, apparently, take place.
Believes species have arisen, like domestic varieties, with much extinction, and that there are no such things as independently created species. Explains why he believes species of the same genus generally have a common or continuous area; they are actual lineal descendants.
Discusses fertilisation in the bud and the insect pollination of papilionaceous flowers. His theory explains why, despite the risk of injury, cross-fertilisation is usual in the animal and vegetable kingdoms, even in hermaphrodites.
States he has "misgivings about the definiteness of species". Believes there is some inherent tendency for plants to originate varieties. Cross-fertilisation is likely in most cases but sees difficulties with plants like Adlumia.
Encloses an abstract of his ideas on natural selection and the principle of divergence; the "means by which nature makes her species".
Discusses varieties and close species in large and small genera, finding some data from AG in conflict with his expectations.
Has been observing the action of bees in fertilising kidney beans and Lobelia.
Thanks AG for his criticisms of CD’s views; finds it difficult to avoid using the term "natural selection" as an agent.
Discusses crossing in Fumaria and barnacles.
Has received a naturally crossed kidney bean in which the seed-coat has been affected by the pollen of the fertilising plant.
Finds the rule of large genera having most varieties holds good and regards it as most important for his "principle of divergence".
Asks whether botanists tend to record varieties more carefully in large genera or small genera.
Wants information on the ranges of varieties of a species compared to the range of the species.
List of close species taken from AG’s Manual of botany [1848].
Discusses the variation of species in large and small genera.
Thanks AG for his list of close species.
Laments the slow progress he makes with his book [Natural selection].
Self-fertilisation in Fumariaceae.
[CD note on bees’ visiting some members of Fumariaceae.]
Believes that, in Dicentra, Fumaria and Corydalis, flower structures are related directly to visits from bees. Flower stigmas generally are placed in the path of bees.
Has received paper from Wallace on natural selection; has sent abstract of his notions, with Wallace’s paper, to Linnean Society.
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.
Wishes to know whether differences in constitution (such as disease susceptibility) are related to differences in complexion. "Liability to such a disease as yellow fever would answer my question in the best possible way."
Sends copy of Origin for comments.
Does not feel AG’s views of migration after the last glaciation explain distribution in U. S. as well as CD’s view of migration prior to glaciation.
Would welcome American edition of Origin.
Thanks for AG’s Japan memoir [Mem. Am. Acad. Arts & Sci. 6 (1857–9): 377–452]. Does not think AG’s arguments for a warm post-glacial period are sufficient, but will not be sorry to be proved wrong.
Believes natural selection explains many classes of facts which repeated creation does not.
Writes of some responses to the Origin.