My dear Hooker

I have been thinking over your note of this morning, which like all your others is of real value to me.— I quite agree with observation on small local genera not varying & mundane ones varying; but this instead of an objection strikes me as rather the very point, which I want to show by my tables.

But I will not discuss the whole subject here; indeed I am trying,as far as able, not to settle my conviction till all my results are finally worked out; when, if you will let me, I will have my M.S. fairly copied out, & sent to you.—

I really cannot at present doubt that for my theoretical object that local Floras are the best; my object being to see whether varieties are not incipient species.—¹ Perhaps you will see my point of view, by taking a strong case; viz Marsupialia might well be an increasing group in Australia & a diminishing one when put into competition with Placentalia in S. America; if I lumped them, the results would be confounded & false for both sides.—

Of course I do not suppose with groups of plants so widely extended as they are, that there ever sh^d. be such difference, as there might be in case of Mammals. Therefore I agree that orders in a Prodromus not obeying my rule as with Labiatæ & Verbenaceæ is a serious objection; though not nearly so fatal, in my opinion, if in a local Flora.—² I was led to all this work by a remark of Fries, that the species in large genera, were more closely related to each other than in small genera;³ & I thought if this were so, seeing that varieties & species are so hardly distinguishable, I concluded that I sh^d. find more varieties in the large genera than in the small: but at first, seeing the many causes of doubt, I certainly did not expect to find more than three-fourths of the Floras, yielding the result, which they have.— But I will not go on; as someday I hope you will read my short discussion on whole subject.—

You have done me infinite service, whatever opinion I come to, in drawing my attention to at least the possibility or the probability of Botanists recording more varieties in the large than in the small genera.—⁴ It will be hard work for me to be candid in coming to my conclusion.—

Ever yours most truly | C. Darwin

I shall be several weeks at my present job.⁵

The work has been turning out badly for me this morning & I am sick at heart & oh my God how I do hate species & varieties.

P.S.⁶ I see that I had not understood your figures— They are quite sufficent, (so I do not care for Book) to show how hostile the result is—⁷ But I look at this as too small an order as any good test; I find to make Balance such as I have always later, there w^d be only 4 genera on one side & one of these gigantic; I very well know how you will sneer at this wriggling out— C. D.

I shall of course allude to your result on Urticeæ⁸