To W. E. Darwin 22 June [1866]1
Down
June 22nd.
Dear William—
I have forwarded the business letters.2
If your case turns out true (wh. it probably won’t) it will be a most interesting discovery & I vow you shall write a paper & publish it; but it must be well worked out first.3 I presume the case is as follows; let us take a long & short-styled primrose and suppose the female organs to abort in both & then we shd have two males; & now take another pair & abort the male organs in both & we shd. have two females; & the case wd be like that of the Rhamnus. In all my speculations I never dreamed of such a case. Now the great thing is to be sure that the pollen grains differ in size in the two males. I have more confidence in measuring a few choice grains with the micrometer than with the camera.4 You say that the grains are largest in what you call the pistillate males i.e. what primordially must have been the long-styled forms. Now it is a universal law in the most different orders, as in Primula Hottonia, Mitchella, Pulmonaria, Menyanthes, Sethia, Lythrum, and Oxalis that the pollen grains from the longer stamens in the short styled form are the largest; & this is unfortunately against yr. view.5 But as the pollen is equal in the two forms of Linum there may be some way of wriggling out of this difficulty.6
Is there any difference in length in the stamens of the two male forms? Are you pretty sure that the two male forms do not graduate into each other; & so with the two female forms? It wd be eminently well to ascertain whether yr. pistillate male sets a few berries. I could detect no difference in length in the rudimentary stamens of the two females. If you are sure about the difference in size in the pollen of the two males, the case must be extraordinary whether or no we can understand it. If you have marked all four forms I would get you in the autumn when the leaves are shedding, to cut me off some branches & I daresay we could make them strike & then I could experimentise on them; I suppose the bushes would be two big to dig up? I could give you the results of any experiments for your paper but this is looking a long way ahead.7
Do not be discouraged if the whole case blows up— I am well accustomed to such explosions.
yr affectate Father | Ch. Darwin (miserable forgery)8 | Ch. Darwin
It wd be well to look at ovules in pistillate male:—9 Asa Gray says in letter that Rhamnus lanceolatus of U. States, has 2 forms, which differ only in pistils— The long-styled is much the most fruitful, but the short-styled does bear some fruit.— He adds that the stamens in the 2 forms were not rigorously compared.—10
Footnotes
Bibliography
Collected papers: The collected papers of Charles Darwin. Edited by Paul H. Barrett. 2 vols. Chicago and London: University of Chicago Press. 1977.
Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.
Forms of flowers: The different forms of flowers on plants of the same species. By Charles Darwin. London: John Murray. 1877.
‘Two forms in species of Linum’: On the existence of two forms, and on their reciprocal sexual relation, in several species of the genus Linum. By Charles Darwin. [Read 5 February 1863.] Journal of the Proceedings of the Linnean Society (Botany) 7 (1864): 69–83. [Collected papers 2: 93–105.]
Summary
Polymorphism in Rhamnus.
Letter details
- Letter no.
- DCP-LETT-5131
- From
- Charles Robert Darwin
- To
- William Erasmus Darwin
- Sent from
- Down
- Source of text
- DAR 185: 15
- Physical description
- LS(A) 4pp
Please cite as
Darwin Correspondence Project, “Letter no. 5131,” accessed on 26 September 2022, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-5131.xml
Also published in The Correspondence of Charles Darwin, vol. 14