Hildebrand’s paper on trimorphism in Oxalis ["Über den Trimorphismus in der Gattung Oxalis", Monatsber. K. Preuss. Akad. Wiss. Berlin (1866): 352–74].

Problems of explaining brightly coloured, attractive seeds.

Haeckel has visited Down.

FM’s climbing plants paper is printed [J. Proc. Linn. Soc. Lond. (Bot.) 9 (1867): 344–9].

Thanks for observations on dimorphic plants. Dimorphism prevalent in certain groups throughout the world.

Retarded fertilisation in certain orchids.

Describes his experiments in fertilising Oncidium flexuosum and comparison with Notylia.

Has been examining Catasetum.

Encloses seeds of two species of Gesneria and describes hairs in the seed capsule. Hairs in other plants seem to have a different function.

Starting tomorrow for a botanical excursion on the Continent.

Thanks for CD’s letter inquiring about capsules produced by the Maxillaria with larger pods [see 5331]. Gives descriptions of Maxillaria and of the other Vandeae.

Describes Oncidium flexuosum.

Tells of botanical results of recent excursion to the German colony Theresopolis. Brought home fine collection of living orchids.

CD’s Variation is in printer’s hands.

Orchid self-sterility.

Observations on orchid self-sterility.

Wants information on characters that may have originated through sexual selection in lower animals.

Encloses queries on expression.

Reports observations on fertility of orchids he has self-pollinated and crossed with pollen of other species.

Thanks for facts on orchids.

Friedrich Hildebrand’s new book on fertilisation of plants [Die Geschlechten-Vertheilung bei den Pflanzen (1867)].

CD correcting proofs of Variation.

FM likes Ernst Haeckel’s book [Generelle Morphologie (1866)].

Cites cases of difference in coloration between the sexes of some species of Crustacea, annelids, and spiders.

Discusses dimorphic plants and self-sterility.

Outlines some experiments involving the crossing of different species of orchids.

Encloses extract from Carl Claus, Die freilebenden Copepoden [1863].

Self-sterility in orchids.

Growth differences in plants raised from self- and cross-fertilised seed.

Thanks for information on sexual differences.

Orchids; self-sterility and difficulty of getting seeds to germinate.

Dimorphism.

Discusses dimorphism in plants, especially the Rubiaceae.

Gives observations on orchids; notes varying degrees of self-sterility and a varying success at crossing distinct species.

Mentions local ferns he is collecting

and considers the phenomenon of apparently mimetic plants.

Thanks CD for sending F. H. G. Hildebrand’s book on fertilisation [Die Geschlechter-Vertheilung bei den Pflanzen (1867)]

and J. D. Hooker’s "Lecture on insular floras".

Describes work on Rubiaceae, Oxalis,

and on crossing orchids. Lists crosses made.

As for CD’s query concerning sexual differences among invertebrates, he gives the case of the local amphipod, Brachyscellus diversilor. Male differs in shape of antennae and coloration.

Also mentions local fish in sea near Sta Catharina which emits melodic tone to attract females.

Has abstracted for insertion in his sterility chapter [Variation 2, ch. 18], FM’s observations of plant’s pollen being poisonous to itself.

Occurrence of mimetic plants.

Colouring of Planariae.

Queries about expressions in crying monkeys.

Has received letter from Hermann Müller on orchid fertilisation.

Has CD ever considered that the colour of seeds of Amarantaceae would attract the attention of birds?

Describes case of a climbing Chamissoa of the local flora.

Variation to be published at end of month.

Dimorphism and self-sterility.

Seed dissemination in Adenanthera.

Sends Variation and would like to hear what FM thinks of Pangenesis.

Thanks for information on expression.

Dimorphic plants;

differences in seed production in cross- and self-fertilised plants.

Is working on sexual selection and is interested in any anomalous sex ratios in lower animals and any sex-related characters.

CD arranging for a translation of FM’s Für Darwin by W. S. Dallas.