Summary

Sending more Candolle volumes for survey of species with well-marked varieties.

Has begun his introduction [to Flora Tasmaniae]; will not make generalisations.

J. D. Dana’s pamphlet too metaphysical for JDH.

Summary

News of Mrs Henslow’s death.

Studying Impatiens, which bears on CD’s problems. Though genus is endemic to India, with over 100 species, CD will be glad to know they do not run into one another.

Summary

Finds CD’s results [of his survey of well-marked varieties from A. P. and Alphonse de Candolle’s Prodromus systematis naturalis regni vegetabilis (1824–73)] "very curious and suggestive". Thinks the Labiatae will present an obstacle to him as it is a very large and distinct order with well-defined species and genera. Would like to see him tackle more volumes of Candolle’s Prodromus, as his case can only be established by evidence from mundane plants. CD should beware of generalising from local species variability. A comparison of C. C. Babington’s and G. Bentham’s [British] Floras [Babington Manual of British botany (1843, 4th ed., 1856); Bentham Handbook of British flora (1858)] would be invaluable. Suggests CD write to Ferdinand Müller and Charles Moore in Australia. Moisture favouring extension of species is important for CD’s view.

Summary

JDH cites W. H. Harvey’s observations on Fucus and David Don’s on Juncus as examples of variations that are independent of climate. There are many such cases. Gives his working scheme for categorising variation.

Summary

He was unaware that varieties occurred proportionately more in large genera.

Recommends a work [Leonard Gyllenhaal, Insecta Suecica, 4 vols. (1808–27)] for tabulating varieties.

Lists "close geographical representatives of Europaean species" based on the species numbers [in T. V. Wollaston, Catalogue of the coleopterous insects of Madeira (1857)].

Summary

Believes, with CD, that extinction may be an important factor in explaining plant distributions, but sees no reason why the several species of a genus must ever have had a common or continuous area. "Convince me of that, or show me any good grounds for it … and I think you would carry me a good way with you". It is just such people as AG that CD has to satisfy and convince.

Feels that the crossing of individuals is important in repressing variation and perhaps in perpetuating the species, but instances some plants in which it cannot, apparently, take place.

Summary

Comments on species with disjoined ranges; does not feel, despite CD’s expectations, that they tend to belong to small families.

Gives the proportion of U. S. trees in which the sexes are separate [see Natural selection, p. 62].

Summary

States he has "misgivings about the definiteness of species". Believes there is some inherent tendency for plants to originate varieties. Cross-fertilisation is likely in most cases but sees difficulties with plants like Adlumia.

Summary

Discusses difficulties involved in deciding which genera are protean in the light of some comments by H. C. Watson.

Summary

Returns CD’s lists [sent with 2184]. Confusion in genera of Silene is great in continental botanic gardens. One would have to know whether C. F. v. Gärtner had the right names for species in his experiments.

Summary

More on kidney bean crosses.

Summary

Refers to CD’s letter of "May last". ARW’s views on order of succession of species are in accordance with CD’s.

Disappointed that his paper ["On the law which has regulated the introduction of new species", Ann. & Mag. Nat. Hist. 2d ser. 16 (1855): 184–96] elicited no discussion; now ARW is trying to prove it. Paper merely states the theory.

On black jaguars breeding inter se: ARW has never heard of a parti-coloured one.

Summary

Gives CD further details of the fertility of the offspring from cross of a yak and Indian cow, the so-called chooboos, whose fertility he has traced to the seventh generation [see Natural selection, pp. 437–8].

Summary

Responds to CD’s article on kidney beans [Collected papers 1: 275–7]. Sends beans as evidence of crossing.

Summary

Lists groups of insects absent from the Madeiran fauna.

Summary

Will shortly return CD’s list of varieties of British plants. Discusses the situations in which different varieties of species are often found and the ranges of varieties relative to those of the species.

Summary

HCW is trying to define what CD means by "variable" genera.

Summary

Suggests CD use the common origin of the French "chef" and the English "head" or "évêque" and "bishop" to illustrate the parallels between extinction and transitional forms in language and palaeontology [see Natural selection, p. 384].

Summary

In reply to CD’s query [see 2072], JDD describes what little is known about the crustacea of the Antarctic and southern lands.

Knows of no species of the cold temperate south identical with those of the cold temperate north.

Summary

Embryology of plants of low systematic order. Comparative development begins only with first post-cotyledonary leaves.

Curt letter to JDH from George Henslow.