1843-1862] ORCHIDS -,"' 



just been looking at Lindley's list in the Vi 600 



and I cannot resist one or two of his great division of 

 Arethu hich includes Vanilla. And as 1 know so well 



the Ophreae, I should like (God forgive me) anyone of the 

 Satyriadae, Disidae and ( 1 ae. 



I fear my long lucubrations will have weai u, but it 



has amused me to write, so forgive me. 



To J. D. Hooker. Letter 601 



Part of the following letter is published in the Life and Letters, the 

 remainder, with the omission of part bearing on the Glen Roy problem, 

 is now given as an example of the varied botanical assistance Darwin 

 received from Sir Joseph Hooker. For the part relating to Verbascum 

 see the Variation of Animals and Plants, Ed. II., 1875, ^'°1- U-, P- 83. 

 The point is that the white and yellow flowered plants which occur in two 

 species of / 'erbascum are undoubted varieties, yet " the sterility which 

 results from the crossing of the differently coloured varieties of the same 

 species is fully as great as that which occurs in many cases when distinct 

 species are crossed." 



The sterility of the long-styled form (B) of Li nu in grandiflorum, with 

 its own pollen is described in Forms of Flowers, Ed. II., p. 87 : his con- 

 clusions on the short-styled form (A) differ from those in the present letter. 



Sept. 28th [1S61]. 



I am going to beg for help, and I will explain why I 

 want it. 



You offer Cypripedium ; I should be very glad of a speci- 

 men, and of any good-sized Yandex, or indeed any orchids, 

 for this reason : I never thought of publishing separately, and 

 therefore did not keep specimens in spirits, and now I should 

 be very glad of a few woodcuts to illustrate my tew remarks 

 on exotic orchids. If you can send me any, send them by 

 post in a tin canister on middle of day of Saturday, Oct 5th, 

 for Sowerby will be here. 



Secondly : Have you any white and yellow varieties 

 Verbascum which you could give me, or propagate for me, 

 or lend me for a year ? I have resolved to try Gartner's 

 wonderful and repeated .statement, that pollen of white and 

 yellow varieties, whether used on the varieties or on distinct 

 species, has different potency. 1 d^ not think any experiment 

 can be more important on the origin of species ; for if h< 

 correct we certainly have what Huxley calls new physiological 

 species arising. 1 should require several species of Verbascum 



