Ɛpsilon

From W. G. Smith   24 July 1877

15, Mildmay Grove, N.

24 July 1877

My dear Sir

During the next day or two I will carefully examine the leaves sent & report with pleasure— They do not however seem especially promising to the fungus eye—1

I have just been observing a most curious thing that will no doubt interest you— When at the B. Musm. last week Mr Carruthers handed me a transparent slice through a fossil Lepidodendron from the Coal Measures (He has recently referred to this slice as containing a fossil fungus, in his address before the Geological Association—the cut he gives is however of no value as it was drawn by some one who knew nothing about fungi)2

There can be no doubt whatever that the parasite in question is a true Pythium & in no way to be distinguished from the species of this genus now living (several species were engraved for me for Gardeners Chronicle July. 1. 1876). No doubt you know the genus well. Berkeley, De Bary, I & many others believe them to be true fungi, other men place them with the Algæ or Saprolegnieæ but this is of no moment as all the plants run together at this point3

Now the curious thing about this fossil Pythium is this— Many of the oogonia are still balanced on their tender threads, and within some of the oogonia the Zoospores may be most distinctly seen in situ

I think the fact of a fossil fungus with fossil zoospores within the Vascular bundles of a Lepidodendron is quite new

Mr Carruthers has given me permission to describe & engrave the plant for publication— The species is the same size as Pythium proliferum De Bary engraved in G. Chron4

Yours faithfully | W. G. Smith

Chas Darwin Esq | F.R.S.

1
No letter from CD to Smith on this subject has been found, but he had evidently sent Smith some leaves of seakale and iris so that Smith could analyse what CD suspected to be fungal damage (see letter from W. G. Smith, 27 July 1877).
2
William Carruthers was keeper of the botany department at the British Museum. Lepidodendron is an extinct genus of tree-like plants closely related to modern club mosses. In the printed version of his 1876 presidential address to the Geologists’ Association, an illustration of ‘mycelium of a fungus in the scaliform axis of a Lepidodendron from the Coal Measures’ was included (Carruthers 1876, p. 22).
3
The engravings appeared with Smith’s article ‘The resting-spores of the potato fungus’, Gardeners’ Chronicle, 1 July 1876, pp. 10–12. Smith refers to Anton de Bary and Miles Joseph Berkeley. The genus Pythium was originally classified as a form of Algae but is currently considered to be a genus of water mould in the class Oomycetes in the kingdom Chromista. Smith later decided that Carruthers’s Pythium was a fossil Peronospora (named by him Peronosporites antiquarius), writing of its relationships, ‘The Peronosporæ are closely allied to the Algæ—so closely, indeed, that De Bary says the species of the former may with reason be compared with the species of one group of the latter, named the Saprolegnieæ; other botanists place the Saprolegnieæ amongst true fungi’ (W. G. Smith 1877, p. 499).
4
See Gardeners’ Chronicle, 1 July 1876, p. 11. Pythium proliferum is a synonym of P. middletonii.

Please cite as “DCP-LETT-11068,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-11068