Algae World: diatom collections

 Walker Arnott collections

Walker Arnott diatom slides, Royal Botanic Garden Edinburgh


The Royal Botanic Garden Edinburgh holds a large collection of slides and unmounted material from G.A. Walker Arnott; the Garden also possesses Walker Arnott's own copy of William Smith's Synopsis of British Diatomaceae, which Arnott has annotated (especially in volume 2). Most of the slides were originally part of the University of Glasgow collections and were transferred to the Scottish Marine Biological Association in the mid 20th century, and from there to the Garden on permanent loan. They have been reunited with a much smaller number of Walker Arnott slides that were already in the Garden. Later (in the early 21st century), residual materials in the University of Glasgow herbarium were also transferred to the Royal Botanic Garden Edinburgh, comprising unmounted material dried down onto mica or glass. Some of these are shown above in their original packets; the four illustrated represent (clockwise from top middle) material from J.T. Norman, G. Norman, the Rev. R. Cresswell, and W. Smith (note his very characteristic backward-sloping script).

The Glasgow and Edinburgh sets of Walker Arnott slides have been combined into a single sequence and reorganized by sample number: Walker Arnott made two series of samples the 'Larger tubes" and the "Smaller tubes" and a handwritten catalogue of these is held by the Natural History Museum in London, but is available from this website (see below). The "Larger tubes" bear numbers (those shown above are 480, 480 and 479 in the "Large tube" set), while slides derived from the "Small tubes" bear numbers prefixed by "S". Previously, the Glasgow set was organized alphabetically according to the first species mentioned on the label. The Walker Arnott collection contains many isotypes for species described by British diatomists in the 1850s.

The unmounted micas are organized according to the species named on the packet, but some also bear numbers corresponding to the "Large tube" or Small tube" series.

In the early 2000s, a handwritten catalogue, listing the two major series of Walker Arnott slides was prepared by a dedicated and careful volunteer, Charles Rawcliffe, who has since died. The catalogue was photographed by Jakub Zdroik during a visit to Edinburgh by him and Dr Aleksandra Zgrundo (University of Gdansk) in 2013; they have kindly made the photographs available here as pdfs.

Downloads (large files!)

David Mann, October 2013

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