[Enclosure]

Thames Ditton

30 May

Dear Dr Hooker

I thank you very much for kindly sending ‘The Student’s Flora’, which I am right glad to see.⁵ It will surely prove a success, and be held a standard for many years to come. If asked the prominent characteristics of the S. F. I might sum up in two pair of words:

‘Condensed completeness— Judicious Selection.’ These characteristics appear alike in the plan of the work as a whole, & in the workmanship in detail.

It is a marvel to me how you have got time for it, considering the many other matters you have to look to, official & individual.

Your Appendix list, as a receptacle for plants which uselessly increase and interfere with the general text of our Floras, makes practical a remark already in print for Part iii of my Compendium Cyb. Brit., which thus, some months hence, will appear as a needless anachronism,— a post-factum suggestion.⁶

You have hit the medium between Bentham’s Handbook & Bab^n’s Manual, in the uexata questio of species;—avoiding the opposite fault or defect of each.⁷ Babington places too many very questionable species on equality with the unquestioned. In avoiding that extreme, one way, Bentham too much neglects them, as real though subordinate forms. I doubt whether either of them has fairly realized to his own mind the obvious fact that “species” are widely non-equivalents, & require treatment accordingly,—that it is not a drop at once from “true species” to “mere variety”, as the expressions usually run.

Of course, opinions will diverge very much in special instances,—between true species, sub-species, variety, variation, etc.— But a great step is gained for the rising botanists by training them through a descriptive Flora to recognize and trace gradations. Among others, C. Darwin ought to thank you for that; the stereotype representations of ‘species’ and ‘variety’ in Floras, even more than the like in Faunas, being barriers to the acceptance of Darwinic views.

As a sample how opinions will differ in the special instances, I should about as soon call the Pear a sub-species of Apple, as some of the plants you place in that relationship; ee: gr. Chenopodium album & ficifolium, or Hypericum quadrangulum & undulatum.⁸ And yet, it must be confessed that some facts side with you, rather than me, in these instances. The Chenopodia & Hyperica have been much confused, or one taken for the other; not so, Pears & Apples, either trees or fruit.

Sincerely Yours | Hewett C^l. Watson