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Darwin Correspondence Project

From W. T. Thiselton-Dyer   31 October 1879

Kew.

Octr. 31. 79

Dear Mr Darwin

Your plant is Lunularia vulgaris.

We have spoken in Sachs of the vegetative structures of this plant as composed of thalloid shoots since they are really laterally expanded axes bearing rudimentary leaves along a central nerve on the under side. To speak of them as fronds would however meet with very general approval (since Hepaticæ with this habit are called frondose) I am not sure that our objection to the shorter expression was not a little pedantic.1

The greenish bodies in the open saucers are perhaps hardly spores but are usually called gemmæ. The similar bodies in Machantia are figured in Sachs (p. 298)2 They really are modified hairs and their gradual development into young plants may be compared to the formation of buds from the leaves of Bryophyllum.3 Of course they tread hard on4 spores which are themselves mostly structures arising asexually for reproduction. But spores I take to be unicellular bodies capable of a period of suspended vitality (e.g. fern spores). These Lunularia hairs grow directly into new Lunularia plants

In Marchantia the containing receptacle has a complete circular margin while in Lunularia it is a crescent.

I have been very unwell with an attack fortunately slight of liver congestion. But I hope and believe I am convalescent again

Believe me | Yours very sincerely | W. T. Thiselton Dyer

CD annotations

End of letter: ‘(I ought to allude to Selaginella. Lycopidiaceæ circumnutating in Chapt I.)’5 pencil

Footnotes

See letter to W. T. Thiselton-Dyer, 29 October 1879. Lunularia vulgaris is a synonym of L. cruciata, the crescent-cup liverwort. Thiselton-Dyer and Alfred William Bennett had translated Julius Sachs’s Text-book of botany from the German (Sachs 1875). On Lunularia see Sachs 1875, p. 298; on their preference for ‘thalloid’ over ‘frondose’, see ibid., p. 296 n. 2. The former taxon Hepaticae is roughly equivalent to Marchantiophyta (liverworts). CD used the term ‘frond’ in Movement in plants, p. 258.
Thiselton-Dyer refers to the translation, Sachs 1875.
Bryophyllum is a former genus, now subsumed within the genus Kalanchoe. The leaves of Kalanchoe species are notable for producing small growing plantlets on their edges that eventually drop off and root.
That is, tread hard upon the heels of, or approach closely to.
In Movement in plants, p. 66, CD described the movements of ‘Selaginella Kraussii (?) (Lycopodiaceae)’. The name is now usually rendered as S. kraussiana (Krauss’s clubmoss); it is now in the family Selaginellaceae in the subclass Lycopodiidae. See also Correspondence vol. 26, letter from W. T. Thiselton-Dyer, 29 January 1878.

Bibliography

Sachs, Julius. 1875a. Text-book of botany: morphological and physiological. Translated and annotated by Alfred W. Bennett, assisted by W. T. Thiselton-Dyer. Oxford: Clarendon Press.

Summary

Terminology for asexual gemmae of Lunularia vulgaris and comparison with Marchantia.

Letter details

Letter no.
DCP-LETT-12281
From
William Turner Thiselton-Dyer
To
Charles Robert Darwin
Sent from
Kew
Source of text
DAR 209.3: 335
Physical description
ALS 6pp †

Please cite as

Darwin Correspondence Project, “Letter no. 12281,” accessed on 8 May 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-12281.xml

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