348 BOTANY [CHAP. XI 



Letter 673 You will see in the new edition of the Origin l why I have 

 alluded to the beauty and bright colours of fruit ; after writing 

 this it troubled me that I remembered to have seen brilliantly 

 coloured seed, and your view occurred to me. There is a 

 species of peony in which the inside of the pod is crimson and 

 the seeds dark purple. I had asked a friend to send me some 

 of these seeds, to see if they were covered with anything which 

 could prove attractive to birds. I received some seeds the 

 day after receiving your letter, and I must own that the fleshy 

 covering is so thin that I can hardly believe it would lead 

 birds to devour them ; and so it was in an analogous case 

 with Passiflora gracilis. How is this in the cases mentioned 

 by you ? The whole case seems to me rather a striking one. 



I wish I had heard of Mikania being a leaf-climber before 

 your paper 2 was printed, for we thus get a good gradation 

 from M. scandens to Mutisia, with its little modified, leaf-like 

 tendrils. 



I am glad to hear that you can confirm (but render still 

 more wonderful) Hackel's most interesting case of Linope. 

 Huxley told me that he thought the case would somehow be 

 explained away. 



To F. Muller. 



Letter 674 



Down [Received Jan. 24th, 1867]. 



I have so much to thank you for that I hardly know how 

 to begin. I have received the bulbils of Oxalis, and your 

 most interesting letter of October ist. I planted half the 

 bulbs, and will plant the other half in the spring. The case 

 seems to me very curious, and until trying some experiments 

 in crossing I can form no conjecture what the abortion of the 

 stamens in so irregular a manner can signify. But I fear 

 from what you say the plant will prove sterile, like so many 

 others which increase largely by buds of various kinds. 

 Since I asked you about Oxalis, Dr. Hildebrand has pub- 

 lished a paper showing that a g- re at number of species are 



1 Origin of Species, Ed. IV., 1866, p. 238. A discussion on the origin 

 of beauty, including the bright colours of flowers and fruits. 



- See Climbing Plants (3rd thousand, 1882), p. 116. Mikania and 

 Mutisia both belong to the Compositae. Mikania scandens is a twining 

 plant : it is another species which, by its leaf-climbing habit, supplies 

 a transition to the tendril-climber Mutisia, F. Miiller's paper is in 

 Linn. Soc. Journ. IX., p. 344. 



