Thursday, 26 July 2012

Grown, pressed, scanned and stamped - but what to call this giant 'salvia'?


Just one of the pretty flowers in the Princess of Wales Conservatory at the moment (and outdoors, in the garden of the Director of Royal Botanic Gardens, Kew I noticed tonight). It's a Brillantaisia, a genus of about 20 species, all native to tropical Africa and Madagascar. They look a bit like salvias, and are sometimes called Giant Salvias, but they are unrelated (being in the plant family Acanthaceae rather than the mint family, Lamiaceae). In the conservatory this plant is labelled Brillantaisia nyanzarum. 

Neither the flowers (at an inch or two from top to bottom) or the plant are particularly huge compared with your typical salvia, so I'm not sure where the name comes from. Worse still, I'm not sure the scientific name is correct either.




Confirming its name revealed some collections of a different kind. We have the Type Specimen of Brillantaisia nyanzarum in our preserved plant collection, the Herbarium, at Royal Botanic Gardens, Kew. A name is attached pretty much forever to its Type Specimen. Whatever else happens, this specimen must remain part of this species. If there is any change in the circumscription of the species (making it narrower or broader in scope) or if it has to be moved to a new species, genus, family or whatever, this specimen tells us where the species name nyanzarum goes. It's important.


So important that we are part of a worldwide project to scan and store images of all our Type Specimens. This is our picture of the Type Specimen of Brillantaisia nyanzarum ('Holotype' is the name given to the most important of the type specimens if there are a number of replicates collected and stored).


As you can read on JSTOR Plant Science, this specimen was collected G.F. Scott Elliot in 1893, from the side of a river near Lake Victoria. It seems from our database that this specimen has been more recently identified as Brillantaisia owariensis, the very first name given to a species of Brillantaisia, in 1818, and therefore taking priority over the name nyanzarum. That is, owariensis as we currently conceive it is an extremely variable species including things that look like our Type Specimen of nyanzarum so we must now use the name Brillantaisia owariensis. Although we have a few dried specimens under the name Brillantaisia owariensis in our herbarium, we don't have its Type Specimen from Nigeria.

You can find more information about both names in the Flora of Tropical East Africa, a comprehensive guide to the plants of this region published by Royal Botanic Gardens, Kew, and also included in JSTOR. The author is Kaj Vollesen, from Kew.


I've checked in The Plant List and sure enough, Brillantaisia owariensis is the name we should now use. So some changes are needed - to our glasshouse label, and to a stamp...


Sometimes taxonomy (the naming of plants) is disparagingly called stamp collecting, as though all we do is pick flowers, press them and then organise them tidily in herbaria. I've got nothing against stamp collecting although I noticed on a site devoted to philately even stamp collectors are defensive about what they do: 'philately is more than simply stamp collecting' it remonstrates. 

So too is taxonomy. It involves plenty of investigation, hypothesis generation and testing, and all the dark arts of science. But if you like a little philately, Brillantaisia nyanzarum graced a Kenyan 20 shilling stamp in 1983. That's what I now call Brillantaisia owariensis of course.

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