The botanist Joseph Dalton Hooker was born 200 years ago, on 30 June 1817. Kew Gardens, of which he was the director, has a special event to commemorate him. Hooker travelled on expeditions to Antarctica, India, Palestine, Morocco, and the Western United States. The pictures below are from his The botany of the Antarctic voyage of H.M. discovery ships Erebus and Terror in the years 1839–1843, under the command of Captain Sir James Clark Ross. He also published several volumes on the botany of India.
In an at times acrimonious process (some have even called it a “wattle war”), the former plant genus Acacia has been split into five genera, with further splits likely. The XVIII International Botanical Congress in 2011 confirmed a previous decision to retain the Acacia name for the largest of the resulting genera, found mainly in Australia:
“Under the internationally accepted rules governing the correct naming of plants, the International Code of Botanical Nomenclature, the name would normally have remained with the African-American group, as this includes the species Acacia nilotica, which is the nomenclatural type species… However, a special provision of the Code allows for the name of the type species of a genus to be changed in cases like this, where strict application of the rules would require a large number of species to be renamed… An application under this provision was made in 2003… This was considered by the relevant botanical committees, who decided in its favour. The International Botanical Congress at Vienna in 2005 ratified this decision. The Vienna decision was contested by a group of botanists involved with African and American acacias. The Melbourne Congress, in two important votes on the first day of the Nomenclature Section, supported the procedure used in Vienna by a large majority. Support for this decision was widespread and not confined to Australian delegates. This vote effectively confirmed that the type species of Acacia is now an Australian species.”
The resulting division of the former Acacia is as follows:
The map below shows the distribution of the new genera, divided into the Americas, Africa, Asia, and Australia & the Pacific (background image from NASA Visible Earth). A degree of reorganisation was going to be needed whatever nomenclature proposal was accepted, but it certainly made sense to retain the Acacia name for 71% of the original species (although Wikipedia, which becomes more and more partisan as time passes, ran a campaign against the official decision for several years). The botanical community seems quite happy using the new names, and it does not seem that the issue will resurface at the XIX International Botanical Congress later this year, although there continues to be debate about how to resolve similar issues in the future.
Here are the five new genera, with examples:
About 13 species, in the Americas. See theplantlist.org.
About 15 species, in the Americas. See theplantlist.org.
About 163 species, throughout the tropics. See theplantlist.org.
About 203 species, throughout the tropics. See theplantlist.org. This genus is likely to be split further.
About 987 species, almost all in Australia and the Pacific.
The Wellcome Library has donated to Wikimedia Commons over 100,000 images relating to medical history, rare books, Asian art, and other topics. The images are available from wikimedia.org (progressively) or from wellcomeimages.org under a Creative Commons Attribution only CC BY 4.0 licence (giving credit to ‘Wellcome Library, London’). Example images from this treasure trove include:
Blow fly (Chrysomya chloropyga) – coloured drawing by Amedeo John Engel Terzi
Indian game of Snakes and Ladders
Arabidopsis thaliana, the thale cress (photo above by Peggy Greb, picture below by Johann Georg Sturm and Jacob Sturm, 1796) is a small flowering plant in the family Brassicaceae – the mustard/cabbage family.
During much of the 20th century, A. thaliana was the target of extensive research, facilitated by the small size of the plant (and of its genome), its short life cycle, and its suitability for light microscopy. Sequencing of the genome was completed in the year 2000, and the genome is available at arabidopsis.org. The open-access peer-reviewed The Arabidopsis Book also collates information on the plant, which is in many ways the botanical equivalent of Caenorhabditis elegans. It has taught the world a great deal.
The Google Ngram below shows the explosion in Arabidopsis-related literature since about 1990, outstripping even work on C. elegans:
A wonderful image of pollen from sunflower, morning glory, hollyhock, lily, primrose, and castor bean plants (Dartmouth Electron Microscope Facility 2011, colourised by William Crochot).
Image of a strawberry by Annie Cavanagh and David McCarthy of the School of Pharmacy, University of London. This beautifully detailed image was created in 2010 by stitching several different SEM images together. I have mentioned this image before. It comes via via Wellcome Images, and more of the story is here.
A human human T-lymphocyte (white blood cell), colourised blue (NIAID 2010).