Summary

A review and criticism of Chauncey Wright’s paper on phyllotaxy [Mem. Am. Acad. Arts & Sci. n.s. 9 (1867–73): 379–415]. Does not believe that the "distributive" and "cyclical" properties, which CW claims characterise the existing spiral orders of leaf arrangement, can be shown to be advantageous to plants. CW’s speculations on the origins of the spiral arrangement of leaves are purely hypothetical.

Summary

On leaf arrangement. [Badly damaged and almost illegible.]

Summary

Outlines his theory on the origin of existing orders of leaf arrangement. Believes spiral and whorled orders have evolved from a primitive distichous arrangement. These arrangements permit a compact bud form of small surface area that can withstand external changes in temperature, and in particular can tolerate frost.

Summary

Thanks CD for reading his MS [8412] and for his suggestions.

Clarifies his statement on the contraction of the bud-axis: did not mean to imply that this contraction occurred in an individual’s life-time, rather that it was the effect, after the course of ages, of successive favourable modifications.

Believes the true theory of phyllotaxy will give a convincing illustration and proof of the theory of evolution.

Summary

Discusses the significance of the node. Believes, with CD, that it has no independent importance but is merely the consequence of the presence of a leaf. Does not believe a distinction can be made between whorled and alternate leaf arrangements on the basis of the number of leaves springing from a node. The node, as the starting point of a leaf, is subject to any disarrangement which takes place among the leaves.

Summary

Corrects a factual error in his previous letter [8418].

Sends specimens illustrative of the "nodal" question.

Summary

Responds to CD’s comments on his MS on phyllotaxy.

The initial variation required by his theory would be a slight twist of the bud-axis; believes the frequent twisting of stems and branches renders such a variation possible.

Admits he placed too much emphasis on the importance of frost. He should have spoken more generally of "vicissitudes of climate".

Summary

Disputes Thomas Meehan’s observations on the hardiness of exposed buds, and believes bud-scales are for the protection of the bud-leaves. Reiterates his opinion that the phyllotaxy of a plant is determined by causes acting when the leaves are crowded into close contact. Attempts to explain how a different phyllotaxy on the upper and lower parts of the same shoot could have arisen.

Summary

Thanks for letter, in which CD cited [Anton] Kerner’s alpine observations.

Describes with diagrams the curious disposition of leaves on some Acacia twigs, and points out that his theory should account for these anomalies as well as normal cases.

Summary

Discusses works lent him by CD: Candolle, Kerner, Braun, Sachs, and CD’s own notes on relative positions of leaves. Plans paper on subject for Royal Society.

Just appointed medical inspector under local government board.