skip to content

Darwin Correspondence Project

From J. D. Hooker   [26 November – 4 December 1860]1

Royal Gardens Kew

in solution will excite electric &c currents & these again would affect vitality—   be this as it may, I cannot but suppose, that if your observations are good they will lead to most important discoveries in Veg. physiology. I saw at Paris2 a sensitive grass! of which they promised me a live plant—   it’s leaves are short & distichous & these close on one another at night; as do those of the sensitive plants. Have you chloroformed your Drosera & then tried it?

I inspected a collection of New Caledonian plants at the Jardin de Plantes that altogether confirms my view of the very close affinity of that Flora with the Australian & diversity from that of the Pacific Islands to the East of it.—   Also more Australian types are turning up in the Phillippines & China.

Another most curious fact of sporadic distribution fell in my way at Paris; when inspecting a small collection of Aden plants I found one that is identical with a Namaqua-land3 plant! & is found no where else hitherto, it is not even found in the Eastern districts of South Africa—   What is still more remarkable is that it belongs to a Natural Order Loaseæ which is otherwise wholly & exclusively American. Another & parallel case is that of Cacteæ , the only Extra American species of which is found only in Tropical Africa & Ceylon. Another is the Papyrus which is found abundantly in Syria, in one spot in Sicily & nowhere else north of the Tropics!

I paid particular attention to your query about the sudden appearance of plants on ascending Lebanon4 & made a good many observations to the effect that the more remarkable forms especially generic do appear very suddenly in great quantities, & am inclined to believe that the lower limit of these is far better defined than the upper limit of those that disappeared.— This applies to Astragalus, Acantholimon, Vicia, & several other plants which are characteristic of the dry soil & climate that prevails above 7000 ft. but not to other plants which are equally peculiar to the elevation but which depend on some little moisture—as Potentilla, &c. The Vegetation above 8000 ft was extremely scanty, & I found but one Alpine or Arctic plant (Oxyria reniformis) & that was close to the tip-top & very rare. This absence of Alpine plants on the Mts of Asia-minor is a very characteristic feature, & is shared, I am assured, by the Mts of Algeria—   Under these Circumstances the presence of so very marked an artic plant as Oxyria is very interesting— it seems to say that an expulsion of other Arctics must have taken place, & the drought would effet this well enough. The Cedars are going owing to the same causes— Every seedling dies, there are no trees under 40–50 years old. from which age up to 500 (perhaps the oldest) there are trees of all (or many) ages.5

I have taken up the Genera Plantarum with Bentham in earnest6 & am going to mend my ways now & for ever—giving up all Societies but the Linnæan, & every unnecessary excitement, keep early hours, cut off all correspondents (except those I love), with short letters— eat well, walk a good deal in the garden & avoid all occasions of sin—   I have not had a headache for 3 months now!

CD annotations

1.1 in solution … it? 1.6] crossed pencil
2.1 I .  .  . ages. 4.17] ‘Limitation of Form on Mountain | Arctic Plants | Sporadic Distrib’ brown crayon
5.1 I .  .  . now! 5.5] crossed pencil

Footnotes

The part of the letter that is now missing apparently included a response to points raised by CD in the preceding letter. See CD’s reply, 4 December [1860]. The letter is dated ‘December 2 [?], 1860’ in L. Huxley ed. 1918, 1: 533.
Hooker passed through France on his way to and from Syria.
Namaqualand was the name given to a region on the west coast of South Africa.
Hooker composed a memoir on the cedars of Lebanon that was published in 1862 (Hooker 1862b).
The proposal to publish a new and complete Genera plantarum had been entertained by Hooker and the botanist George Bentham since 1859. They began work in March 1860 (see letter to J. D. Hooker, 12 March [1860]). The first part of the first volume was published in 1862 (Bentham and Hooker 1862–83).

Summary

Encourages CD’s work in vegetable physiology.

Ascending the Lebanon JDH noted limits of plant distribution as CD requested: lower limits of a genus sharper than upper. Sharpness of boundaries related to a plant’s moisture requirement.

Impressed by "sporadic" distribution at the Jardin des Plantes in Paris.

Letter details

Letter no.
DCP-LETT-3000
From
Joseph Dalton Hooker
To
Charles Robert Darwin
Sent from
unstated
Source of text
DAR 100: 158–60
Physical description
††

Please cite as

Darwin Correspondence Project, “Letter no. 3000,” accessed on 20 July 2019, https://www.darwinproject.ac.uk/letter/DCP-LETT-3000.xml

Also published in The Correspondence of Charles Darwin, vol. 8

letter