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.
Please cite as “DCP-LETT-8105,” in Ɛpsilon: The Charles Darwin Collection accessed on