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Darwin Correspondence Project

To Hugo de Vries   [15] August [1878]1

Abinger Hall

Aug. 16th

My dear Sir

How easy it is to see a thing when it has once been pointed out! I pulled up some wild parsnips & the upper part of the primary root was finely corrugated with transverse folds.— The one sent grew on edge of little cliff, & the upper part must have been kept very dry, & it was much more corrugated than the roots of these plants.2 I daresay you have thought of exposing plant, so that upper part of root might be kept very dry or damp.—

I will mention one other point: farmers say that young wheat (Triticum) plants are easily ejected by frosts out of the ground, so that they profit by the ground being trampled or rolled. Therefore I pulled up some plants of wheat & with a pocket lens could see no corrugation. Can this have any connection with the abortion of the primary root in the Gramineæ?3 Forgive me for scribbling thus & amusing myself.—

I much enjoyed seeing you yesterday & remain | Yours very faithfully | Ch. Darwin

I have written to Asa Gray


The date is established by the reference to De Vries’s visit (see n. 2, below). CD wrote 16 in error; the letter was written the day after De Vries’s visit on 14 August.
De Vries visited CD at Abinger on 14 August 1878 (Emma Darwin’s diary (DAR 242)). De Vries had discussed the contraction and folds of roots of Trifolium pratense (red clover) in an article on the stages of growth of the plant (Vries 1877c, pp. 927–30).
The phenomenon of frost uplifting soil is referred to as frost heaving. It occurs in soils with a pore structure that allows capillary flow for the formation of ice lenses. For more on the mechanics of the phenomenon, see Taber 1930. Plants of the family Gramineae (a synonym of Poaceae, grasses), such as Triticum (the genus of wheat), have a network of seminal roots, rather than a single primary root.


Taber, Stephen. 1930. The mechanics of frost heaving. Journal of Geology 38: 303–17.


Enjoyed seeing HdeV yesterday.

Following the point mentioned by HdeV, CD has observed the difference in corrugation of primary roots in plants exposed to dry and damp soil.

Letter details

Letter no.
Charles Robert Darwin
Hugo de Vries
Sent from
Abinger Hall
Source of text
Artis Library (De Vries 4b)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 11662,” accessed on 18 April 2021,