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Darwin Correspondence Project

From Richard Spruce   [1876–7]1

Note for Mr. Darwin.

In consulting my MSS. lately for evidence as to the relationship between Tiliaceæ & Passifloreæ I came on the following instances of Dimorphism.2

The species of the Tiliaceous genus Mollia are low trees with long, distichous leaves, and axillary star-like flowers with white petals as large as those of Passiflora cærulea.3 In four species of my gathering (M. speciosa Mart., lepidota S. tomentosa S., longifolia S.) the numerous stamens are grouped in 5 outer, and 5 inner shorter cohorts—the former with pink purple or pale violet filaments & anthers, and green pollen—the latter with yellow anthers & pollen.4 Length of style not noted.

In Luhea altheæflora S., which has large purple flowers, the numerous stamens, with yellow anthers & pollen, are encompassed by an outer row of slender violet anantherous filaments—plainly a relique of a former dimorphous condition.5

In L. paniculata6 Mart. there is also an outer row of shorter and anantherous filaments.

In the curious Leguminous genus Swartzia the stamens are notably dimorphous, & in one species (S. grandifolia Bong.) they are apparently tetramorphous.7

RS.

CD annotations

3.1 Mollia] underl red crayon
3.4 longifolia S.)] scored red crayon
3.6 Length of style not noted.] underl red crayon
End of letter: ‘Luhea (Tiliaceæ)’ ink; ‘R. Spruce | stamens of different colours in same flower’ pencil
Verso of letter: ‘[‘Spec’ del] Look to Lagerstrœmia’ ink; ‘in⁠⟨⁠   ⁠⟩⁠ all species of’8 blue crayon; ‘Perhaps anthers alone of Mollia cd be spared— if so examine with lens stigmas | Leucosmia— Harvey— A. Gray Thymelaceæ’9 ink

Footnotes

The date range is established by CD’s notes on Mollia, made for Forms of flowers, which was published in 1877 (see n. 4, below). CD worked on Mollia only in relation to Forms of flowers.
Tiliaceae (formerly the family of linden or basswood) is now subsumed within the family Malvaceae (mallows). Passifloreae is a synonym of Passifloraceae, the passion-flower family.
Passiflora caerulea is bluecrown passion flower.
All the species of Mollia mentioned are native to South America, especially Brazil and Columbia. CD obtained specimens of M. lepidota and M. speciosa from the Royal Botanic Gardens, Kew; his notes are in DAR 110: B19. Although undated, the notes were made on the reverse of a proof-sheet of Cross and self fertilisation, which he would have received between 19 August and 21 October 1876 (CD’s ‘Journal’ (Correspondence vol. 24, Appendix II)). Additional notes on M. lepidota, written by Francis Darwin, are in DAR 109: B118 and DAR 110: B12. In Forms of flowers, p. 168 n., CD mentioned the information on Mollia, but erroneously attributed it to ‘Mr Spence’.
Luehea altheiflora (misspelled Luhea altheaeflora by Spruce) is a synonym of Lueheopsis althaeiflora, another species formerly classified within the Tilliaceae. CD had been interested in the possibility of intermediate stages in floral morphology, such as a dimorphic structure developing into a dioecious one (see, for example, Correspondence vol. 14, letter to W. E. Darwin, 22 June [1866]). In Forms of flowers, p. 168 n., CD discussed the possibility that flowers of Mollia and Luehea might be heterostyled, but having observed some of the flowers himself, concluded this was not the case.
Luehea paniculata.
Swartzia grandifolia is big leafed swartzia; its flowers have dimorphic stamens.
Lagerstroemia is the genus of crape myrtle in the family Lythraceae; stamens of plants in this genus are typically dimorphic with dimorphic pollen. CD had recorded this in notes made between 5 and 24 August 1863 (DAR 109: B116–17). In Forms of flowers, pp. 167–8, CD discussed the variability of the stamens in L. indica (crape myrtle), and hypothesised that it might have reverted from a former heterostyled state.
Leucosmia is a synonym of Phaleria, a genus in the family Thymelaeaceae (formerly known as Thymeleae). In a letter of 4 December 1876 (Correspondence vol. 24), CD asked Asa Gray for flowers of Leucosmia in order to compare the size of pollen-grains and state of the stigma. In Forms of flowers, pp. 114–15, CD cited Gray’s article ‘New or little known Polynesian Thymeleæ’ (A. Gray 1865, p. 305) as a source for information on L. burnettiana (a synonym of Phaleria disperma) and L. acuminata (a synonym of Phaleria acuminata). Gray mentioned that there was a better specimen of L. burnettiana at Kew that had been collected by William Henry Harvey (see Correspondence vol. 24, letter from Asa Gray, 22 December 1876).

Bibliography

Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.

Cross and self fertilisation: The effects of cross and self fertilisation in the vegetable kingdom. By Charles Darwin. London: John Murray. 1876.

Forms of flowers: The different forms of flowers on plants of the same species. By Charles Darwin. London: John Murray. 1877.

Gray, Asa. 1865d. New or little-known Polynesian Thymeleæ. Journal of Botany 3: 302–6.

Summary

Notes on various instances of dimorphic stamens.

Letter details

Letter no.
DCP-LETT-4372
From
Richard Spruce
To
Charles Robert Darwin
Sent from
unstated
Source of text
DAR 109: B119
Physical description
Amem 1p ††

Please cite as

Darwin Correspondence Project, “Letter no. 4372,” accessed on 28 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-4372.xml

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