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Darwin Correspondence Project

From Francis Darwin   [12 September 1878]1

6 Queen Anne St

My dear Father,

Here are some tubes Hawksley sent to see whether they wd do, they look pretty good tho’ the walls are thick. They draw them out over flame & have to guess the right moment to stop pulling so it is impossible to get any size accurately except by making a lot & picking some out. The sample quills are strung on a bit of red strap with the tubes2

I have had 2 days hard work at Kew, very successfully, Lynch the head foreman gathers the leaves & brings them in to me all with the names marked.3 It would be an endless job for me to hunt out where each plant is & I should think he is trustworthy   I have impressed on him the awful consequences of mistakes   I frightened him so by asking whether he was sure that 2 plants were rightly named that he took them to the Herbarium & they were right. I have been rather horrified at finding out mistakes in the number of stomata given in my books, I was led to look at the stomata myself by seeing how badly they suited Sachs theory.4 One Broussonettia was given as having all its stomata above & I found it was an ordinary tree-leaf wetting perfectly above & hairy underneath, & I found very few st above & lots on the undersurface.5 Vicia sativa was given as no stomata above, & as the bloom is only on the upper side I looked at stomata & found far more above than below.6 I sent the plant to the Herbarium to make sure. Some mistake may be misprints such as the under side stoma being put in upper side column, or wrong figure &c. Or the Germans & I may be looking at different plants. I have done 3 or 4 sp of primula & they suit Sachs theory well

P. marginata has most bloom above & stomata 16 above/1 below

P. capitata exactly vice versâ in both bloom & stomata. The meal of primulæ must be very bad protection as it washes off on dipping the leaf in water.7 I am not sure it wouldn’t pay better to only count stomata myself but it is so awfully slow compared to using other peoples observations.

Horace was here to dinner on Tuesday & went on to Cambr same night & comes he tomorrow to see Wm off   H. seemed very well & jolly. Uncle Ras is pretty well.8 I dont see much of him, I leave here 7·45 am & get back 6·45 pm. Hooker was away when I called. Dyers have gone9

I am glad to here ubbadubba10 is jolly | Yrs affec | F D

After all I will send glass tubes separate from this letter


The day and month are established by the relationship between this letter and the letter to Francis Darwin, 12 September [1878], and by the reference to the departure of the Thiselton-Dyers (see n. 9, below); the year is established by F. Darwin 1886, p. 99, where Francis wrote that he did the work described in this letter in 1878.
CD and Francis used clear and blackened glass tubes, and quills, to enclose the tips of cotyledons of plants while observing the effects of light on the lower parts; see Movement in plants, pp. 470 and 478. Hawksley: possibly Thomas Paton Hawksley, a surgical-instrument maker in London who patented clinical thermometers in 1870 (Woodcroft 1871, p. 450).
Richard Irwin Lynch was helping Francis with his work at the Royal Botanic Gardens, Kew, on stomata on leaves, which was part of his and CD’s investigations of bloom on plants; CD did not publish on bloom, but see F. Darwin 1886.
Julius von Sachs thought that bloom protected the stomata of plants from water (Sachs 1868b, p. 178; F. Darwin 1886, p. 99).
Broussonetia is the genus of paper mulberries. Francis listed Broussonettia (sic) papyrifera as having no bloom on its leaves and stomata only on the undersides in F. Darwin 1886, p. 104; for his source, see Weiss 1865, p. 133.
Vicia sativa is common vetch. Francis listed it as having more stomata on the undersides than the upper sides of its leaves, and bloom only on the upper surface, in F. Darwin 1886, p. 109. Francis listed four sources for his original determination of the number and position of stomata in F. Darwin 1886, p. 102: Czech 1865, Kareltschikoff 1866, Morren 1863, and Weiss 1865. Czech 1865, Morren 1863, and Weiss 1865 did not mention Vicia, while Kareltschikoff 1866, p. 272, said it had more stomata on the undersides than the upper sides of its leaves.
See F. Darwin 1886, p. 114. Primula marginata is the silver-edged primrose; P. capitata is the round-headed Himalayan primrose.
Francis was staying with his uncle Erasmus Alvey Darwin in London, where his brothers Horace and William Erasmus Darwin had visited him. William and his wife Sara were on their way to visit Sara’s relatives in Boston, Massachussetts (letter from Emma Darwin to W. E. Darwin, 17 September [1878] (DAR 219.1: 115)); they sailed on 14 September (Emma Darwin’s diary (DAR 242)).
Joseph Dalton Hooker was director of the Royal Botanic Gardens, Kew; William Turner Thiselton-Dyer was the assistant director. Thistleton-Dyer’s wife, Harriet Anne, was Hooker’s daughter. The Thiselton-Dyers left for a month-long tour of Switzerland on 12 September 1878 at 6:45 in the morning (William Turner Thiselton-Dyer’s diary, Archives, Royal Botanic Gardens, Kew).
Bernard Darwin, Francis’s son.


Czech, Karl. 1865. Untersuchungen über die Zahlverhältnisse und die Verbreitung der Stomata. Botanische Zeitung, 31 March 1865, pp. 101–7.

Darwin, Francis. 1886. On the relation between the ‘bloom’ on leaves and the distribution of the stomata. [Read 4 February 1886.] Journal of the Linnean Society (Botany) 22 (1885–6): 99–116.

Kareltschikoff, S. 1866. Über die Vertheilung der Spaltöffnungen auf den Blättern. Bulletin de la Société impériale des naturalistes de Moscou 39: 260–97.

Morren, Édouard. 1863. Détermination du nombre des stomates chez quelques végétaux indigènes ou cultivés en Belgique. [Read 5 December 1863.] Bulletins de l’Académie royale des sciences, des lettres et des beaux-arts de Belgique 2d ser. 16: 489–509.

Movement in plants: The power of movement in plants. By Charles Darwin. Assisted by Francis Darwin. London: John Murray. 1880.

Weiss, Adolf, 1865. Untersuchungen über die Zahlen- und Grössenverhältnisse der Spaltöffnungen. Jahrbücher für wissenschaftliche Botanik 4 (1865–6): 125–96.

Woodcroft, Bennet. 1871. Alphabetical index of patentees and applicants for patents of invention, for the year 1870. London: Office of the Commissioners of Patents for Inventions.


He has been working hard at Kew for two days.

Letter details

Letter no.
Francis Darwin
Charles Robert Darwin
Sent from
6 Queen Anne St, London
Source of text
DAR 274.1: 44

Please cite as

Darwin Correspondence Project, “Letter no. 11690F,” accessed on 6 March 2021,