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Darwin Correspondence Project

To J. S. Henslow   23 [August or September 1855]1

Down

23d

My dear Henslow

The enclosed Umbellifer has made me very unhappy: I cannot make it out: will you name it for me? I hate the whole Family. It grew 3–4 ft high. in rather moist thicket. To save trouble I send envelope all ready directed.—

On account of two statements made by naturalists, viz (one) that the most “typical form of a species is that which produces most seed,”2 I am very anxious to compare number of seed of wild & cultivated plant (I can easily see how false the above aphorism is, but I want precise facts) & I most curiously forgot it wd. not suffice to count seeds of one umbel of Wild Celery so will you get one of your little girls to get very finest 12 wild Celery near you, & either count (& pay well for me) all the seeds, or count umbels, & count seeds in an average umbel.— I can manage Carrot & Parsnip myself, & have wild & tame plants, marked. I have got Wild Cabbage & asparagus, also, in hand.— (our wild Parsnips are poor, so perhaps it wd be good to let some little girls count.)3 There has been another more wonderful statement made than even the above,—viz that rich cultivation (not merely of the individual but of the race) lessens the fertility of all organic beings, by which assumption several authors (as I daresay you may have noticed) have attempted to upset Malthus’ most logical writings—4 I mention all this just to show that my odd wishes are not absolutely idle.

Most truly your’s | C. Darwin

Footnotes

The letter could have been written in either August or September when the wild celery and carrot usually set seed, as mentioned in the letter. Although CD was away from home a good deal in September (see ‘Journal’; Correspondence vol. 5, Appendix I) he had returned to Down by 22 September.
CD’s remark was derived from Arthur Henfrey’s observation in a paper delivered at the Botanical Society of London in March 1849 and reported in the Phytologist 3, pt 2 (1849): 488–9. Henfrey had said that he considered the best example of a true species in the Phanerogamia was that ‘in which the seeds (the highest product) were most perfectly and abundantly produced, in a generally healthy condition of the whole plant, and from such examples alone, where any doubt existed, should specific characters be drawn’. CD read volume three of the Phytologist in April 1854 (Correspondence vol. 4, Appendix IV, 128: 10). His notes on this volume are in DAR 73: 93–113.
CD gave the results of Henslow’s and his own counting, in the context of a different problem, in Natural selection, p. 176 n. He cited the figure of 2250 seeds from the wild parsnip counted by Henslow and 12,000 from one he had gathered. A wild carrot had 40,000 seeds.
Doubleday 1842, Godwin 1820, and Hickson 1849 are cited on this point in Natural selection, p. 89 and n. 2. The discussion of the fertility of wild, compared with cultivated, plants was not completed in Natural selection (p. 88) but is treated at some length in Variation 2: 112–13. CD there stated that ‘comparing beds of carrots saved for seed in a nursery garden with wild plants, the former seemed to produce about twice as much seed’ (p. 113).

Summary

Asks JSH to identify an umbellifer.

Describes his efforts to compare number of seeds of wild and cultivated plants.

Asks that more wild celery be collected and seeds counted. Seeks to verify whether "most typical form produces most seed" and whether cultivation lessens fertility.

Letter details

Letter no.
DCP-LETT-1748
From
Charles Robert Darwin
To
John Stevens Henslow
Sent from
Down
Source of text
DAR 93: A112–13
Physical description
4pp

Please cite as

Darwin Correspondence Project, “Letter no. 1748,” accessed on 19 March 2019, http://www.darwinproject.ac.uk/DCP-LETT-1748

Also published in The Correspondence of Charles Darwin, vol. 5

letter