1857.] LARGE GENERA VARYING. 463 



species only strongly marked varieties. The subject is in 

 many ways so very important for me ; I wish much you would 

 think of any well-worked Floras with from 1000-2000 species, 

 with the varieties marked. It is good to have hair-splitters 

 and lumpers.* I have done, or am doing : — 



Babington 



Henslow 



London Catalogue. 



Boreau . 



Miquel . 



Asa Gray 



Hooker . 



Wollaston 



:* British Flora. 

 H. C. Watson 3 

 France. 

 Holland. 

 N. U. States. 

 N. Zealand. 



Fragment of Indian Flora. 

 Madeira insects. 



Has not Koch published a good German Flora ? Does 

 he mark varieties ? Could you send it me ? Is there not 

 some grand Russian Flora, which perhaps has varieties 

 marked ? The Floras ought to be well known. 



I am in no hurry for a few weeks. Will you turn this in 

 your head when," if ever, you have leisure? The subject is 

 very important for my work, though I clearly see many causes 

 of error. . . . 



C. Darwin to Asa Gray. 



Down, Feb. 21st [1859]. 



My dear Gray, — My last letter begged no favour, this 

 one does : but it will really cost you very little trouble to 

 answer to me, and it will be of very great service to me, owing 

 to a remark made to me by Hooker, which I cannot credit, 

 and which was suggested to him by one of my letters. He 

 suggested my asking you, and I told him I would not give 

 the least hint what he thought. I generally believe Hooker 



* Those who make many species are the "splitters," and those who 

 make few are the "lumpers." 



