Asks correspondent whether, when growing hollyhocks, he finds it necessary to space out the different varieties to prevent crossing and thus to obtain true seed [see Variation 2: 108].
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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.
Asks correspondent whether, when growing hollyhocks, he finds it necessary to space out the different varieties to prevent crossing and thus to obtain true seed [see Variation 2: 108].
Encloses strawberry blossoms used in his crossing experiments.
Sends CD seeds of Cattleya crispa as requested [see Collected papers 2: 77–8].
Anticipates success for his attempts to cross orchids artificially. Has not had a single seed germinate from a pod that was not produced by artificial crossing.
Conducted crosses on Gladiolus varieties exactly according to CD’s letter. Flowers of same variety are self-sterile, whether from the same plant or not.
Studying self-sterility, particularly in Oncidium, where abortion occurs consistently but stigma functions normally. His hybrid orchid crosses show sterility occurs capriciously. Thus it is not a "special endowment".
Disputes Asa Gray’s and Hermann Crüger’s view of rostellar germination.
Doubts absolute sterility of Catasetum.
Disappointed by results with homomorphic cowslips.