skip to content

Darwin Correspondence Project

From J. D. Hooker   7 December 1856


Decr. 7th/56

Dear Darwin

I have roughly done your N.Z. list & am glad to have had my attention drawn to the subject I have roughly marked your list & have made a separate calculation with some slight modifications, due, partly to swaying to & fro between what to call monœcious & what diœcious, & partly to a few additions.1 The Upshot is that I find on adding up my data, 756 species. (some of this 26 over your list is due to unnumbered species & perhaps some to over calculation on my part, I suppose 6 or 8 errors of the latter kind will not influence result.

I make now 108 trees in all; whereas in N. Zeald Flora Introd Essay XXVIII I say there are 113—a near enough hit considering how vague the terms are, which it would be easy to cook into exact accordance or further discordance.2 I say N.Z. Fl. l.c. 156 shrubs & plants with woody stems I now make 150—which is near enough also (far nearer both than I anticipated; for I did not at all remember even approximately what I had done before, & made my calculations before looking to the Introd Essay.3

I also say l.c. that “considerably more than 200 have unisexual, or incomplete flowers as far as reproduct: organs go. I now make the number 234.

I was a great deal too wise in my generation to say in N.Z. Flora how many are monoeecious, dioecious & polygamous for I find that I cannot do this with any approach to accuracy— Perhaps very few are really everlastingly & unalterably dioecious: & I do not think that my diœcious figure is too small.— On the other hand no doubt diag 1. sundry of my hermaphrodite plants may be virtually though abnormally

monœcous 2. Many of my monœcious may bear many perfect flowers, as Clematis 3. Many of my hermaphrodite have normally unisexual flowers mixed with the

♂♀ 4 Lastly various dioecious trees often bear a few flowers of the other sex.

On the opposite side you have the best approximation I can give.


Hermaph. Monœcious Dioecious Herbs 379 102* 19 Shrubs 88 30 31 Trees 56 40. 12. * including 55 Compos. The results will be satisfactory to your theory.4 ramme

I will do the V.D.L. Flora for you far better in a couple of months.5

I dare say that you will not be so surprized as I was at Lyell’s asking my wife if I was the author of the Review (very laudatory of self) in Ed. Review of ADC. + Fl. Ind. + N.Z. Essay—to me the idea is monstrous & revolting—he must think of me all the same as of Owen. by way of mending the matter, when my wife told him I was not, he added that he did not think it very well done!6 This latter bit tickled me amazingly, I can afford that, but not the first imputation. Poor Lady L.7 who was present, seemed much annoyed, my wife laughed at it all, happily— had it been my mother—the Lord have mercy on poor Lyell’s bones— Pray do not let this go further than your own house. I would not that poor Lyell heard of it again.

Ever Yrs | Jos D Hooker

Do tell us how Mrs Darwin is when you next have occasion to write—

Clematis, dioecious but some ♂ flowers have a few ripening pistilla

Viola. hermaphrodite but the winter flowers which have scarcely any stamina appear to be the most productive (? is this so in the N.Z. sp.) Compositæ. I class with monœcious. Grasses various called ♂♀ have also ♂ flowers.

CD annotations

1.5 756] underl pencil; ‘say about 750’ added pencil
2.1 108] underl pencil
Paragraph five: On the table CD has added in pencil an extra row of figures totalling the figures for herbs and shrubs ‘467 132 50’ and an extra column of figures (including an entry for his extra row) headed ‘Mono & Dioec’ totalling the figures for these classes ‘121 61 182 52’. 379] ‘121 added under, pencil —— 500’ In margin of table: ‘108 149 500 —— 757’ added pencil ‘88 30 31 —— 149’ added pencil
Top of first page: ‘allude to cause of doubt—’ pencil


See letter to J. D. Hooker, 1 December [1856]. The list, in the back of CD’s copy of the introductory essay of J. D. Hooker 1853–5 in the Darwin Library–CUL, has been annotated in pencil by Hooker.
See J. D. Hooker 1853–5, 1: xxviii.
See J. D. Hooker 1853–5, 1: xxviii. Hooker’s abbreviation ‘l.c.’ stands for ‘loc. cit.’ CD used the information given in this letter in Natural selection, p. 62.
CD’s theory was that trees tended to have separate sexes (see Natural selection, pp. 61–2).
Hooker was working on his flora of Tasmania (J. D. Hooker 1855[–60]).
Hooker refers to the review of A. de Candolle 1855, J. D. Hooker and Thomson 1855, the introductory essay of J. D. Hooker 1853–5, and T. Moore 1855 that was published in Edinburgh Review 104 (1856): 490–518. The author was George Bentham (Wellesley index 1: 506).


Candolle, Alphonse de. 1855. Géographie botanique raisonnée ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle. 2 vols. Paris: Victor Mason. Geneva: J. Kessmann.

Hooker, Joseph Dalton. 1853–5. Flora Novæ-Zelandiæ. 2 vols. Pt 2 of The botany of the Antarctic voyage of HM discovery ships Erebus and Terror, in the years 1839–1843, under the command of Captain Sir James Clark Ross. London: Lovell Reeve.

Moore, Thomas. 1855. The ferns of Great Britain and Ireland. Edited by John Lindley. London.

Natural selection: Charles Darwin’s Natural selection: being the second part of his big species book written from 1856 to 1858. Edited by R. C. Stauffer. Cambridge: Cambridge University Press. 1975.

Wellesley index: The Wellesley index to Victorian periodicals 1824–1900. Edited by Walter E. Houghton et al. 5 vols. Toronto: University of Toronto Press. London: Routledge & Kegan Paul. 1966–89.


Has done New Zealand flora calculations. Results support CD’s theory of necessity of crossing. Trees tend to have separate sexes.

Letter details

Letter no.
Joseph Dalton Hooker
Charles Robert Darwin
Sent from
Source of text
DAR 100: 113–14
Physical description
ALS 4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 2014,” accessed on 17 May 2022,

Also published in The Correspondence of Charles Darwin, vol. 6