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Darwin Correspondence Project

From Hubert Airy   12 December 1871

Flamsteed House. | Greenwich | London S.E.

1871. Dec. 12.

My dear Sir

Pray accept my ⁠⟨⁠    ⁠⟩⁠ for your very kind l⁠⟨⁠    ⁠⟩⁠ for the help you give m⁠⟨⁠    ⁠⟩⁠ learning something about ⁠⟨⁠ph⁠⟩⁠yllotaxy. Nägeli’s observa⁠⟨⁠tion⁠⟩⁠ seems to be a⁠⟨⁠n⁠⟩⁠ important one; and, if borne o⁠⟨⁠ut⁠⟩⁠ by the facts, will make rather for tha⁠⟨⁠n⁠⟩⁠ against my view, I conceive.1 For I ⁠⟨⁠sh⁠⟩⁠d suppose (till I find his own ⁠⟨⁠wo⁠⟩⁠rds) he means that the bud in its earliest dissect-able condition—in the summer—has its emb⁠⟨⁠ryonic⁠⟩⁠ leaves in some disorder and gradually acquires an orderly arrangement as it swells into the full winter-bud. This would certainly favour my view, that the orderly arrangement is due t⁠⟨⁠o⁠⟩⁠ the need of economy of space, ⁠⟨⁠  ⁠⟩⁠ng especially felt when ⁠⟨⁠    ⁠⟩⁠ leaves are swelling a ⁠⟨⁠    ⁠⟩⁠ta the autumn. As far as ⁠⟨⁠my⁠⟩⁠ observations go, ⁠⟨⁠the⁠⟩⁠ young le⁠⟨⁠aves ar⁠⟩⁠e arranged in perfect order in the ⁠⟨⁠win⁠⟩⁠ter-bud, and I have often found it easy to determine the leaf-arrangement in the bud, when it was most difficult to d⁠⟨⁠o⁠⟩⁠ so in the developed twig, on ac⁠⟨⁠cou⁠⟩⁠nt of unequal twists in ⁠⟨⁠the⁠⟩⁠ internodes. My attempts ⁠⟨⁠at⁠⟩⁠ dissection of summer-buds (⁠⟨⁠    ⁠⟩⁠ hiding at the base of the green leaf) h⁠⟨⁠ave⁠⟩⁠ not been successful.

We might look for evidence from embryology, in leaves as in animals. —May we regard the axillary bud as a kind of parthenogenetic ovary of the leaf to which it belongs?

Let me thank you f⁠⟨⁠or⁠⟩⁠ your k⁠⟨⁠ind⁠⟩⁠ offer to lend me Mr Wright’s ⁠⟨⁠p⁠⟩⁠aper when you have i⁠⟨⁠t a⁠⟩⁠t liberty2   I shall be very glad indeed to see it. I heard the Rev. G. Hensl⁠⟨⁠ow⁠⟩⁠ deliver a lecture on Phyll⁠⟨⁠otaxis⁠⟩⁠ at the Victoria Institute i⁠⟨⁠n⁠⟩⁠ the early part of the year.3 It was a capital exposition of the ⁠⟨⁠pur⁠⟩⁠ely mathematical and mystic ⁠⟨⁠v⁠⟩⁠iew, but that was just what I ⁠⟨⁠had⁠⟩⁠ lately escaped from, and I ⁠⟨⁠wa⁠⟩⁠s not satisfied. He made m⁠⟨⁠uch⁠⟩⁠ of a few irregularities (notably ⁠⟨⁠    ⁠⟩⁠ to be fou⁠⟨⁠nd in⁠⟩⁠ the stem ⁠⟨⁠of⁠⟩⁠ the Jer⁠⟨⁠usalem⁠⟩⁠ artichoke) ⁠⟨⁠    ⁠⟩⁠ ⁠⟨⁠see⁠⟩⁠med to be unacquainted with ⁠⟨⁠in⁠⟩⁠stances of regular irregularity su⁠⟨⁠ch⁠⟩⁠ as that in Spanish che⁠⟨⁠stn⁠⟩⁠ut.4 It is curious to see how the same tree will sometimes affect different leaf-orders in different shoots. The laurel, for instance⁠⟨⁠,⁠⟩⁠ has two ranks of leaves on its latera⁠⟨⁠l⁠⟩⁠ twigs, but you w⁠⟨⁠i⁠⟩⁠ll ⁠⟨⁠o⁠⟩⁠ften find ⁠⟨⁠a⁠⟩⁠ healthy leading-shoot with five. The same is the case ⁠⟨⁠with the     ⁠⟩⁠ nut and the ivy.5

⁠⟨⁠    ⁠⟩⁠ will remember the platysma against the next shivering fit I see or feel.6

With many thanks I remain | My ⁠⟨⁠de⁠⟩⁠ar Sir | Yours very sincerely | Hubert Airy

Charles Darwin Esqre. F.R.S.


This letter was previously published in Correspondence vol. 19; after conservation, more text has become visible. Airy had suggested that the form of the bud was an important element in phyllotaxy (see Correspondence vol. 19, letter from Hubert Airy, 9 December 1871 and n. 3). In his reply, CD had cited Carl Wilhelm von Nägeli’s observation that the position of leaves in the bud was not fixed (see ibid., letter to Hubert Airy, 10 [December] 1871 and n. 6).
Airy refers to Chauncey Wright. See Correspondence vol. 19, letter to Hubert Airy, 10 [December] 1871.
George Henslow’s lecture ‘Phyllotaxis; or, the arrangement of leaves in accordance with mathematical laws’ (Henslow 1871) was read on 20 February 1871.
For Henslow’s comments on the variable phyllotaxis in the Jerusalem artichoke (Helianthus tuberosus), see Henslow 1871, p. 133. The Spanish chestnut is Castanea sativa; it has a variable phyllotaxis which is usually 2/5 in the main vertical shoots, but 1/2 in the horizontal shoots.
The laurel (Laurus nobilis), nut (probably a reference to Corylus avellana, common hazel), and ivy (Hedera helix) have variable phyllotaxis.
CD had mentioned his interest in the contraction of the platysma muscle while shivering in his letter to Airy of 10 [December] 1871 (Correspondence vol. 19).


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.

Henslow, George. 1871a. Phyllotaxis; or, the arrangement of leaves in accordance with mathematical laws. [Read 20 February 1871.] Journal of the Transactions of the Victoria Institute 6 (1873): 129–40.


Thanks for letter and reference to Nägeli’s observations on leaf arrangement in the bud.

Letter details

Letter no.
Hubert Airy
Charles Robert Darwin
Sent from
Source of text
DAR 159: 14
Physical description
ALS 6pp damaged

Please cite as

Darwin Correspondence Project, “Letter no. 8105,” accessed on 8 June 2023,

Also published in The Correspondence of Charles Darwin, vol. 19