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Darwin Correspondence Project

From Francis Darwin   [26? October 1873]1

1   Enormously the largest number of Desmodium are trifoliate; some are unifoliate tre and uni leaves sometimes occurring in the same plant—2 In the uni ones the stipellæ of the lateral leaflets could not be seen— There were no intermediate leaves between uni & tri these lat: leaflets are either present & of normal size or quite gone— The general relation between lat & term leaflets which exists through the whole genus (except D gyrans3 and a very few others) is this; the terminal leaflet is bigger than the lateral ones about in the propn term is to lat. as 7-:6- Dr Hooker4 called the later subequal to the terminal ones— The relation is very variable—

2   D-gyroides5 sometimes nearly subequal—see plan6

3   None have tendrils; no evidence of any being climbers—

Second Letter7

District makes no difference in the relation of lat. to term in D. gyrans— There were very small points to some leaves in some species but not anything but what is found in many leguminosæ—(Dr H)

The little leaflets appear very fugacious8 in D. Gyrans being often broken off—Dr H believes one must have dropped off in the ones you looked at— The leaflets are opposite.

CD annotations

1.1 trifoliate] underl red crayon
1.1 unifoliate 1.2] ‘uni’ underl red crayon
1.2 tre and uni] underl red crayon
5.1 term] before ‘leaflet’ interl pencil


The date is conjectured on the supposition that Francis wrote this memorandum after visiting Kew on Sunday 26 October 1873 (see letter to J. D. Hooker, 23 October [1873]).
CD had asked Francis to look at Desmodium species held at the Royal Botanic Gardens, Kew (see letters to Francis Darwin, 10 October 1873, 22 October 1873, and 23 October [1873]). He thought the plant might have evolved from a climber.
Desmodium gyrans, the telegraph or semaphore plant, is now known as Codariocalyx motorius.
Joseph Dalton Hooker was director of the Royal Botanic Gardens, Kew.
Desmodium gyroides is now Codariocalyx gyroides.
Francis’s working notes, presumably made at Kew, are in DAR 209.2: 18–20, and include a line drawing or ‘plan’ of a leaf of Desmodium gyroides.
The ‘second letter’ is the letter to Francis Darwin of 23 October [1873] (the first being the letter to Francis of 22 October 1873).
Fugacious: easily shed.


Observations on the leaves of Desmodium. Most are trifoliate; none has tendrils. Gives some comments from Hooker.

Letter details

Letter no.
Francis Darwin
Charles Robert Darwin
Sent from
Source of text
DAR 209.2: 21–2
Physical description
Amem 2pp †

Please cite as

Darwin Correspondence Project, “Letter no. 9115,” accessed on 21 October 2021,

Also published in The Correspondence of Charles Darwin, vol. 21