43O BOTANY [CHAP. XI 



Letter 760 rudiments of additional leaflets are present, we must believe 

 that they were well developed in the progenitor of the plant. 

 So again, when the first true leaf differs widely in shape from 

 the older leaves, and resembles the older leaves in allied 

 species, is it not the most simple explanation that such leaves 

 have retained their ancient character, as in the case of the 

 embryos of so many animals? 



Your suggestion of examining the movements of vertical 

 leaves with an equal number of stomata on both sides, with 

 reference to the light, seems to me an excellent one, and 

 I hope that my son Francis may follow it up. But I. will not 

 trouble you with any more remarks about our book. My son 

 will write to you about the diagram. 



Let me add that I shall ever remember with pleasure 

 your visit here last autumn. 



Letter 76i To J. Lubbock (Lord Avebury). 



Down, April i6th [1881]. 



Will you be so kind as to send and lend me the Desmodium 

 gyrans by the bearer who brings this note. 



Shortly after you left I found my notice of the seeds in the 

 Gardeners Chronicle^ which please return hereafter, as I have 

 no other copy. I do not think that I made enough about the 

 great power of absorption of water by the corolla-like calyx 

 or pappus. It seems to me not unlikely that the pappus of 

 other Compositae may be serviceable to the seeds, whilst 

 lying on the ground, by absorbing the dew which would be 

 especially apt to condense on the fine points and filaments 

 of the pappus. Anyhow, this is a point which might be 

 easily investigated. Seeds of Tussilago, or groundsel, 2 emit 

 worm-like masses of mucus, and it would be curious to ascer- 

 tain whether wetting the pappus alone would suffice to cause 

 such secretion. 3 



1 " Note on the Achenia of Pttmilio argyrolepis" Gardeners' 

 Chro7iicle, 1861, p. 4. 



' It is not clear whether Tussilago or groundsel (Senecio vulgaris) is 

 meant ; or whether he was not sure which of the two plants becomes 

 slimy when wetted. 



3 See Letter 707. 



