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Darwin Correspondence Project

From William Saunders   22 November 1877

Canada | London Ontario

Novr 22/77

Chas Darwin Esq

Dear Sir

I send you by todays mail a package of Plants which I trust will be of some interest to you as illustrating the effects of Hybridization. The package contains six plants—2 of Doolittle Black Cap—2 of Philadelphia and 2 Hybrids marked 70 and 72. The Doolittle Blk Cap is an improved variety of the American Black Raspberry Rubus occidentalis which originated in New York and propagates itself by rooting from the tips of the wood of the current year. The Philadelphia is a chance seedling of Rubus strigosus1 found wild in the county of Philadelphia Pa and propagates itself by suckers from the root. The fruit of the former is black, that of the latter red

In 1870 I operated on the flowers of the Doolittle Blk Cap with pollen from the Philadelphia and succeeded in ripening a number of seeds of this cross from which I obtained the following season 35 plants. As one object I had in view was the raising of hardy varieties I gave these young seedlings no protection in winter, hence six died from exposure. The 29 which survived were planted out on my farm and all have fruited. In every one there were plain evidences of intermixture in foliage and fruit, but all rooted at the tip and in three or four instances I have found a sucker thrown up from the roots as well at distances varying from 3 or 4 to 12 inches from the crown. As my primary object was the obtaining of valuable fruits I rejected all that were not promising in this respect and those I send you nos 70 and 72 are among the best. The fruit is intermediate both in color and flavor between that of the two parents, in fact when a berry of the Doolittle and Philadelphia is mixed together and compared with the Hybrids the taste is so identical that it is difficult to distinguish the one from the other. The berry of the hybrids may be called a purple cap; the stool which it sits on is intermediate in form between the Doolittle and Philadelphia, you will observe also that there is a difference in the character of the roots

These new fruits will I believe prove valuable being very hardy and wonderfully prolific. The only difficulty in the way of their general introduction is that they are somewhat difficult to propagate—they do not root readily from the tips and sucker very rarely. A friend of mine who is trying to grow them for me has partly got over this difficulty by burying the new wood in the fall an inch or two below the surface when he finds the following spring that each bud sends up a small fruiting branch and at the base of each of these a cluster of roots is formed

I send you also some reports of the commissioner of agriculture for Ontario for 1872 and 1873 in which you will find further details in regard to this matter on the pages where you will find leaves turned down. You may possibly find other details which will interest you in the Report for 1872 in my paper “Experiments in Hybridizing”2

From our mutual friend the late B. D. Walsh of Illinois and also from C. V. Riley of Missouri I have heard of your kind courtesy which may be given as one reason why I have ventured thus to trespass on your time which I know must be extremely valuable

Yours very respectfully | Wm Saunders


Rubus strigosus is a synonym of R. sachalinensis var. sachalinensis.
CD’s copy of the 1872 report is in the Darwin Library–Down; his copy of the 1873 report has not been found. In the report of 1873, there was an account of a visit to Saunders’s fruit farm, including a discussion of his Doolittle–Philadelphia hybrids (Beadle et al. 1873, pp. 258–9). The paper on hybridity is Saunders 1872.


Sends plant specimens of a hybrid he has raised by crossing two species of Rubus. Describes procedure by which he obtained them. Cites his paper on hybridisation.

Letter details

Letter no.
William Saunders
Charles Robert Darwin
Sent from
London, Ontario
Source of text
DAR 177: 39
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 11248,” accessed on 27 September 2021,