478 'DIFFERENT FORMS OF FLOWERS [1862. 



say,* and it did not occur to me, about no improbability of 

 specialisation in certain lines in lowly organised beings. I 

 could hardly doubt that the hermaphrodite state is the 

 aboriginal one. But how is it in the conjugation of Con- 

 fervas — is not one of the two individuals here in fact male, 

 and the other female ? I have been much puzzled by this 

 contrast in sexual arrangements between plants and animals. 

 Can there be anything in the following consideration : By 

 roughest calculation about one-third of the British genera of 

 aquatic plants belong to the Linnean classes of Mono and 

 Dicecia; whilst of terrestrial plants (the aquatic genera being 

 subtracted) only one-thirteenth of the genera belong to these 

 two classes. Is there any truth in this fact generally ? Can 

 aquatic plants, being confined to a small area or small com- 

 munity of individuals, require more free crossing, and there- 

 fore have separate sexes ? But to return to one point, does 

 not Alph. de Candoile say that aquatic plants taken as a 

 whole are lowly organised, compared with terrestrial ; and 

 may not Oliver's remark on the separation of the sexes in 

 lowly organised plants stand in some relation to their being 

 frequently aquatic ? Or is this all rubbish ? 



.... What a magnificent compliment you end your re- 

 view with ! You and Hooker seem determined to turn my 

 head with conceit and vanity (if not already turned) and make 

 me an unbearable wretch. 



With most cordial thanks, my good and kind friend, 



Farewell, 



C. Darwin. 



[The following passage from a letter (July 28, 1863), to 

 Prof. Hildebrand, contains a reference to the reception of the 

 dimorphic work in France : — 



" I am extremely much pleased to hear that you have been 



* " Forms which are low in the scale as respects morphological com- 

 pleteness may be high in the scale of rank founded on specialisation of 

 structure and function." — Dr. Gray, in ' Silliman's Journal.' 



