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Darwin Correspondence Project

To J. D. Hooker   30 July [1866]

Down

July 30

My dear Hooker

Many thanks about the Lupine. Your letter has interested me extremely & reminds me of old times.1 I suppose by your writing, you would like to hear my notions. I cannot admit the Atlantis connecting Madeira & Canary Islands without the strongest evidence & all on that side: the depth is so great; there is nothing geologically in the islands favouring the belief; there are no endemic mammals or batrachians;2 did not Bunbury shew that some orders of plants were singularly deficient?3 But I rely chiefly on the large amount of specific distinction in the insects & land-shells of P. Santo & Madeira; surely Canary & Madeira cd not have been connected if Mad. P. Santo had long been distinct.4 If you admit Atlantis, I think you are bound to admit or explain the difficulties.

With respect to cold temperate plants in Mad: I of course know not enough to form an opinion; but admitting Atlantis I can see their rarity is a great difficulty; otherwise seeing that the latitude is only a little N. of the Persian Gulph & seeing the long sea transport for seeds, the rarity of N. plants does not seem to me difficult.5 The immigration may have been from a Southerly direction & it seems that some few African, as well as coldish plants are common to the Mts to the South.6

Believing in occasional transport, I cannot feel so much surprize at there being a good deal in common to Mad. & Canary; These being the nearest points of land to each other.7 It is quite new & very interesting to me what you say about the endemic plants being in so large a proportion rare Species. From the greater size of the workshop (i.e. greater competition & greater number of individuals &c) I shd expect that continental forms, as they are occasionally introduced, wd always tend to beat the insular forms; & as in every area there will always be many forms more or less rare tending towards extinction, I shd certainly have expected that in Islands a large proportion of the rarer forms wd have been insular in their origin.8 The longer the time any form has existed in an island, into which continental forms are occasionally introduced, by so much the chances will be in favour of it’s being peculiar or abnormal in nature, & at the same time scanty in numbers. The duration of its existence will also have formerly given it the best chance, when it was not so rare, of being widely distributed to adjoining archipelagos. Here is a wriggle; the older a form is the better the chance will be of its having become developed into a tree!9 An island from being surrounded by the sea will prevent free immigration & competition, hence a greater number of ancient forms will survive on an island than on the nearest continent whence the island was stocked; & I have always looked at Clethra & the other extra-european forms as remnants of the tertiary flora which formerly inhabited Europe.10 This preservation of ancient forms in islands appears to me like the preservation of ganoid fishes in our present fresh waters.11

You speak of no northern plants on mountains south of the Pyrenees; does my memory quite deceive me that Boissier published a long list from the mountains in southern Spain?12

I have not seen Woollaston’s catalogue but must buy it, if it gives the facts about rare plants which you mention.13

And now I have given more than enough of my notions which I well know will be in flat contradiction with all yours. Remember that you have to come here if you possibly can before Nottingham.14

Wollaston in his Insecta Maderiensis 4to. p. xii & in his Variation of Species p. 82– 87 gives case of Apterous insects, but I remember I worked out some additional details. I think he gives in these same works the proportion of European insects.—15

I shd be most grateful for loan of Book with enclosed Title, if you have it; for I presume I could no how else see it—16

Yours affect | C. Darwin

Footnotes

See letter from J. D. Hooker, [24 July 1866]. On CD’s earlier debates with Hooker about geographical distribution, see the letter to Charles Lyell, 15 February [1866], n. 6.
See letter from J. D. Hooker, [24 July 1866] and n. 8. In 1856, CD had objected to the Atlantis hypothesis, citing the same reasons as evidence against a continental connection between Madeira and Africa (Correspondence vol. 6, letter to Charles Lyell, 25 June [1856]). On the Atlantis hypothesis, see Forbes 1846, especially pp. 348–9. For CD’s views on the means by which oceanic islands were populated, see Origin, pp. 388–406.
Charles James Fox Bunbury had noted the absence from Madeira of many European plants which would have been expected if Madeira and Europe had formerly been connected (C. J. F. Bunbury 1855, pp. 19–20); CD’s lightly annotated unbound copy of C. J. F. Bunbury 1855 is in the Darwin Library–CUL. Among CD’s notes on island floras is a record of a conversation dated 25 March 1855 in which Bunbury had said that Cistus and Ophrys did not grow in Madeira, and that northern genera in Madeira were represented by different species from those of the mainland (DAR 205.4: 68).
Porto Santo lies within 50 km of Madeira in the Madeiran archipelago, over 500 km from the Canary Islands. Richard Thomas Lowe had found the land snails of Madeira and Porto Santo to be very different (Lowe 1854; see also Correspondence vol. 5). For the geological inferences drawn from Lowe’s observation, see, for example, Correspondence vol. 8, letter from Charles Lyell, [13–14 February 1860] and n. 10. On the differences between the land shells of Porto Santo and Madeira and those of other islands, see the letters from R. T. Lowe, 19 September 1854 (Correspondence vol. 5).
In his letter of [24 July 1866], Hooker had noted the absence of alpine and subalpine plants in Madeira. Hooker and CD held differing views of the means by which plants were distributed among continents and islands (see, for example, Correspondence vol. 13, letter to J. D. Hooker, 22 and 28 [October 1865] and nn. 11–13). The colonisation of islands, and the differences between island and continental species, are discussed in Origin, pp. 388–406. CD considered that continental extension, as in Edward Forbes’s Atlantis hypothesis, would have resulted in more continental species on islands than are actually found; instead, CD suggested that the rarity of continental species on islands was attributable to distance from the mainland and to the subsequent modification by natural selection of any species that had reached an island by occasional transport (see Origin, pp. 396–9).
In Origin, pp. 367–8, CD described the migration of temperate plants at the end of the glacial period. Hooker’s observation that native plants of Madeira were also to be found in the Cameroon mountains is in his letter of [24 July 1866]. Bunbury had described species of plants common to the Cape region of South Africa and the mountains around Funchal in the south of Madeira (C. J. F. Bunbury 1855, p. 5).
In his letter of [24 July 1866], Hooker had written about certain rare species of plants present in both Madeira and the Canaries, though not in the coastal zones, and Hooker had suggested that this could be explained according to the hypothesis of continental extension. For CD’s belief in the importance of occasional, or accidental, means of transport in the colonisation of islands by plants, see Origin, pp. 356–65. CD’s definition of occasional transport encompassed the transport of seeds by the sea and by animals, especially birds flying across the sea from one land mass to another (Origin, pp. 358–65).
Hooker discussed the rarity of endemic Madeiran plants in his letter of [24 July 1866]. CD suggested that naturalised plant species on islands and mountains could become dominant over native ones owing to the larger areas or ‘workshops’ for natural selection in which the naturalised species had originated in Origin, pp. 379–80.
On CD’s and Hooker’s joke about ‘wriggling’, see the letter to Charles Lyell, 15 February [1866], n. 11. In Origin, p. 392, CD gave a similar account of the possibility that, on islands that had been treeless, trees might have developed gradually by the action of natural selection on the most vigorous herbaceous plants. For CD’s initial observations of vegetation that ‘deserved the title of a wood’ in the Galápagos Islands, see ‘Beagle’ diary, p. 361.
Clethra is a genus of sixty-four tropical American and Asian species, with one species in North America and one in Madeira (Mabberley 1997). In Origin, p. 107, CD noted Oswald Heer’s view that the flora of Madeira resembled the extinct tertiary flora of Europe (see Heer 1855, p. 8 et seq.).
CD argued that the survival of primitive forms was favoured on islands and in fresh water, because competition between organisms was less pronounced in those environments than on continents or in oceans, in Origin, pp. 106–7. As an illustration CD referred to the ‘remnants of a once preponderant order’, the freshwater ganoid fishes, arguing that there was less competition in any freshwater basin than in the sea (Origin, p. 107).
CD refers to Pierre-Edmond Boissier and to Boissier 1839–45. Boissier 1839–45 includes lists of mountain plants from the province of Granada in southern Spain that also occur in the Pyrenees, and in the French and Swiss Alps, together with a table of the altitudes at which the plants are found in the different regions (Boissier 1839–45, 1: 227–8, 237–8).
CD misunderstood the references to Thomas Vernon Wollaston in the letter from J. D. Hooker, [24 July 1866], as implying that he had published a new work on the plants of Madeira. However, Wollaston’s publications about the Atlantic islands were confined to their entomology and conchology.
Hooker visited CD in Down on 18 August before giving his lecture on insular floras at the meeting of the British Association at the Advancement of Science in Nottingham on 27 August 1866 (see letters from J. D. Hooker, [17 August 1866] and 18 August 1866).
CD refers to T. V. Wollaston 1854, p. xii, and T. V. Wollaston 1856, pp. 82–7; there is an annotated copy of the former, and a heavily annotated copy of the latter, in the Darwin Library–CUL (see Marginalia 1: 875–9). CD’s detailed abstract of T. V. Wollaston 1854, with his additional calculations of the proportions of winged and apterous beetles on Madeira, is in the Darwin Archive–CUL (DAR 197: 1). Inside the back cover of his copy of Insecta Maderensia (T. V. Wollaston 1854), CD pasted his own estimate of the number of endemics among the insect species mentioned in the book. Although Wollaston noted that some of the 200 apterous beetles of Madeira were also distributed in Europe (T. V. Wollaston 1856, p. 83; see also T. V. Wollaston 1854, p. xiii), no specific proportion was given in the works to which CD refers here. CD quoted Wollaston’s data on the apterous beetles of Madeira in Origin, pp. 135–6.
The enclosure has not been found.

Bibliography

‘Beagle’ diary: Charles Darwin’s Beagle diary. Edited by Richard Darwin Keynes. Cambridge: Cambridge University Press. 1988.

Boissier, Pierre-Edmond. 1839–45. Voyage botanique dans le midi de l’Espagne pendant l’année 1837. 2 vols. Paris: Gide et Cie.

Bunbury, Charles James Fox. 1855. Remarks on the botany of Madeira and Teneriffe. [Read 6 March and 3 April 1855.] Journal of the Proceedings of the Linnean Society (Botany) 1 (1857): 1–35.

Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

Forbes, Edward. 1846. On the connexion between the distribution of the existing fauna and flora of the British Isles, and the geological changes which have affected their area, especially during the epoch of the Northern Drift. Memoirs of the Geological Survey of Great Britain, and of the Museum of Economic Geology in London 1: 336–432.

Heer, Oswald. 1855. Ueber die fossilen Pflanzen von St. Jorge in Madeira. [Read 5 November 1855.] Neue Denkschriften der allgemeinen Schweizerischen Gesellschaft für die gesammten Naturwissenschaften n.s. 5 (1857): paper 2.

Lowe, Richard Thomas. 1854. Catalogus Molluscorum pneumonatorum Insularum Maderensium: or a list of all the land and fresh-water shells, recent and fossil, of the Madeiran Islands. Proceedings of the Zoological Society of London pt 22: 161–218.

Mabberley, David J. 1997. The plant-book. A portable dictionary of the vascular plants. 2d edition. Cambridge: Cambridge University Press.

Marginalia: Charles Darwin’s marginalia. Edited by Mario A. Di Gregorio with the assistance of Nicholas W. Gill. Vol. 1. New York and London: Garland Publishing. 1990.

Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.

Wollaston, Thomas Vernon. 1854. Insecta Maderensia; being an account of the insects of the islands of the Madeiran group. London: John van Voorst.

Wollaston, Thomas Vernon. 1856. On the variation of species with especial reference to the Insecta; followed by an inquiry into the nature of genera. London: John van Voorst.

Summary

His reasons for rejecting Atlantis hypothesis connecting Madeira and Canary Islands.

Letter details

Letter no.
DCP-LETT-5167
From
Charles Robert Darwin
To
Joseph Dalton Hooker
Sent from
Down
Source of text
DAR 115: 294, 294b
Physical description
6pp

Please cite as

Darwin Correspondence Project, “Letter no. 5167,” accessed on 5 June 2020, https://www.darwinproject.ac.uk/letter/DCP-LETT-5167.xml

Also published in The Correspondence of Charles Darwin, vol. 14

letter