352 B|OTANY [CHAP. XI 



Letter 676 the comparison of the growth of plants produced from self- 

 fertilised and crossed seeds. I began this work last autumn, 

 and 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-fertilised 

 and 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. 

 Many thanks for the dimorphic Rubiaceous plant. Three of 

 your Plumbagos have germinated, but not as yet any of 

 the Lobelias. 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 

 and of any excursions which you might take ? I feel certain 

 that you might make a very valuable and interesting book, 

 for every one of your letters is so full of good observations. 

 Such books, for instance Bates' Travels on the Amazons, 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. He is an excellent good fellow, 

 as well as naturalist. He has lately published a pamphlet, 1 

 which I think you would like to read ; and I will try and 

 get a copy and send you. 



To F. Mullen 



Letter 677 



The following refers to the curious case of Eschscholtzia described in 

 Cross and Self -Fertilisation, pp. 343-4. The offspring of English plants 

 after growing for two generations in Brazil became self-sterile, while the 

 offspring of Brazilian plants became partly self-fertile in England. 



Jan. 30th [1868]. 



. . . The flowers of Eschscholtzia when crossed with pollen 

 from a distinct plant produced 91 per cent, of capsules ; when 

 self-fertilised the flowers produced only 66 per cent, of capsules. 

 An equal number of crossed and self-fertilised capsules con- 

 tained seed by weight in the proportion of 100 to 71. 



1 Sir J. D. Hooker's lecture on Insular Floras, given before the British 

 Association in August, 1866, is doubtless referred to. It appeared in the 

 Gardeners' Chronicle, and was published as a pamphlet in January, 1867. 

 This fact helps to fix the date of the present letter. 



