310 BOTANY [CHAP. X 



Letter 635 flower of A. Loddigesii. I have got both species from Ke\v, 

 but whether we shall have skill to flower them I know not. 

 One conjectures that it is imperfect male ; I still should 

 incline to think it would produce by seed both sexes. But 

 you are right about Primula (and a very acute thought it 

 was) : the long-styled P. sinensis, homomorphically x fertilised 

 with own-form pollen, has produced during two successive 

 homomorphic generations only long-styled plants. The 

 short-styled the same, i.e. produced short-styled for two 

 generations with the exception of a single plant. I cannot 

 say about cowslips yet. I should like to hear your case of 

 the Primula : is it certainly propagated by seed ? 



Letter 636 To J. Scott. 



Down, Dec. 3rd, [1862?]. 



What a capital observer you are ! and how well you have 

 worked the primulas. All your facts are new to me. It is 

 likely that I overrate the interest of the subject ; but it seems 

 to me that you ought to publish a paper on the subject. It 

 would, however, greatly add to the value if you were to cover up 

 any of the forms having pistil and anther of the same height, 

 and prove that they were fully self-fertile. The occurrence of 

 dimorphic and non-dimorphic species in the same genus is 

 quite the same as I find in Linum? Have any of the forms of 

 Primula, which are non-dimorphic, been propagated for some 

 little time by seed in garden ? I suppose not. I ask because 

 I find in P. sinensis a third rather fluctuating form, apparently 

 due to culture, with stigma and anthers of same height. I 

 have been working successive generations homomorphically of 

 this Primula, and think I am getting curious results ; I shall 

 probably publish next autumn ; and if you do not (but I 

 hope you will) publish yourself previously, I should be glad 

 to quote in abstract some of your facts. But I repeat that I 

 hope you will yourself publish. Hottonia is dimorphic, with 

 pollen of very different sizes in the two forms. I think you 

 are mistaken about S ipJw campy lus, but I feel rather doubtful 



1 In Forms of Flowers, Ed. il., p. 216, a summary of the transmission 

 of forms in the "homomorphic" unions of P. sinensis is given. Darwin 

 afterwards used " illegitimate " for homomorphic, and " legitimate " for 

 " heteromorphic " (Forms of Flowers, Ed. I., p. 24). 



2 Darwin finished his paper on Linum in Dec. 1862, and it was 

 published in the Linn. Soc. Journal in 1863. 



