My dear Darwin

Your grass appears to me to be Festuca pratensis & agrees as ill with the descriptions as most plants do— How on Earth you have made out 30 grasses rightly is a mystery to me— You must have a marvellous tact for appreciating diagnoses. I am sure that I could not have done it. I very much rejoice at your feats, as it will afford us many subjects of interest in common—when we meet again. I think that some structural points would interest you—as that of the inflorescence of grasses. Amongst facts of interest & which will one day be licked into shape pro or con species & migration is that of the South coast of Australia— I have just made a resumeé of the Australian Leguminosæ,² about 900 species.— Of these some 450 inhabit the South West Corner Swan River &c & about 300 the South East. (New South Wales &c) but there are not 10 species common to both! Now what can migration be about, trans-water or trans-land—& what a busy time of it Dame Nature has had in making so many species, whether by creation or variation.

I am busy at Indian Compositæ.³ There are two very common English thistles a small one Carduus acanthoides & a big C. nutans. I never heard of their being supposed to be varieties by any one & they differ in many points; but the Himal. specimens are all of an intermediate form.— its small states identical with acanthoides, its large with small nutans

These facts shake species to their foundation—but according to my view of species, as contrasted with other systematists, there are sore few of them. In fact if there were a possibility of bringing your & my opinions to book, it might prove that we were not so far divided. The more I study the more vague my conception of a species grows, & I have given up caring whether they are all pups of one generic type or not—that the main forms remain so long distinct, that we may through their characters, trace their distribution, is certainly all we can expect to prove in our day; & the laws of that distribution more than we shall establish in our life-time— Have you read Baden Powell—⁴ I was extremely disappointed with it.

Ever yrs | Jos D Hooker