To Fritz Müller 22 April 1
Down. | Bromley. | Kent. S.E.
My dear Sir
I am very sorry your papers on climbing plants never reached you.2 They must be lost, but I put the stamps on myself, & I am sure they were right. I despatched on the 20th all the remaining copies, except one for myself. Your letter of Mar 4th contained much interesting matter,3 but I have to say this of all your letters.
I am particularly glad to hear that Oncidium flexuosum is endemic, for I always thought that the cases of self-sterility with orchids in hot-houses might have been caused by their unnatural conditions.4 I am glad also to hear of the other analogous cases, all of which I will give briefly in my book that is now printing.5 The lessened number of good seeds in the self-fertilized Epidendrons is to a certain extent a new case.6 You suggest the comparison of the growth of plants produced from self-fertilized & crossed seeds; I began this work last autumn & the result in some cases has been very striking, but only as far as I can yet judge with exotic plants which do not get freely crossed by insects in this country. In some of these cases it is really a wonderful physiological fact to see the difference of growth in the plants produced from self-fertilized & crossed seeds, both produced by the same parent-plant; the pollen which has been used for the cross having been taken from a distinct plant that grew in the same flower-pot.7 Many thanks for the dimorphic rubiaceous plant.8 Three of your Plumbagos have germinated, but not as yet any of the lobelias.9 Have you ever thought of publishing a work which might contain miscellaneous observations on all branches of natural history, with a short description of the country & of any excursions which you might take. I feel certain that you might make a very valuable & interesting book, for every one of your letters is so full of good observations. Such books, for instance Bates’s Travels on the Amazons,10 are very popular in England.
I will give your obliging offer about Brazilian plants to Dr. Hooker, who was to have come here to day, but has failed.11 He is an excellent good fellow, as well as naturalist: He has lately published a pamphet, which I think you wd like to read, & I will try & get a copy & send you.12
Yours most sincerely. | C. Darwin
Self-sterility in orchids.
Growth differences in plants raised from self- and cross-fertilised seed.