328 BOTANY [CHAP. X 



Letter 653 as he is a most laborious and able man, with the manners 

 almost of a gentleman. 



The following is an abstract of the paper which was enclosed in the 

 letter to Asa Gray. 



Pp. 106-8. Red cowslip by variation has become non- 

 dimorphic, and with this change of structure has become 

 much more productive of seed than even the heteromorphic 

 union of the common cowslip. Pp. 91-2, similar case with 

 Auncula ; on the other hand a non-dimorphic variety of P. 

 farinosa (p. 115) is less fertile. These changes, or variations, 

 in the generative system seem to me very remarkable. But 

 far more remarkable is the fact that the red cowslip 

 (pp. 106-8) is very sterile when fertilising, or fertilised by 

 the common cowslip. Here we have a new " physiological 

 species." Analogous facts given (p. 98) on the crossing of 

 red and white primroses with common primroses. It is very 

 curious that the two forms of the same species (pp. 93, 94, 

 95, and 117) hybridise with extremely different degrees of 

 facility with distinct species. 



He shows (p. 94) that sometimes a cross with a quite 

 distinct species yields more seed than a homomorphic union 

 with own pollen. He shows (p. m) that of the two homo- 

 morphic unions possible with each dimorphic species the 

 short-styled (as I stated) is the most sterile, and that my 

 explanation is probably true. There is a good summary to 

 the paper. 



Letter 654 To J. D. Hooker. 



The following letters to Hooker, April ist, April 5th and May 22nd, 

 refer to Darwin's scheme of employing Scott as an assistant at Down, 

 and to Scott's appointment to the Botanic Garden at Calcutta. 



Down, April ist, 1864. 



I shall not at present allude to your very interesting 

 letter (which as yet has been read to me only twice !), for 

 I am full of a project which I much want you to consider. 



You will have seen Scott's note. He tells me he has no 

 plans for the future. Thinking over all his letters, I believe 

 he is a truly remarkable man. He is willing to follow 

 suggestions, but has much originality in varying his ex- 

 periments. I believe years may pass before another man 

 appears fitted to investigate certain difficult and tedious 



