Julian Shaw

Cullen, J. 2011. Naturalised Rhododendrons widespread in

Great Britain and Ireland, Hanburyana 5: 11–19. Cullen, J. 2015. Rhododendron. In: Stace, C.A., Preston, D.C. & Pearman, D.A. Hybrid flora of the British Isles. Botanical

Society of Britain and Ireland, Bristol, p.225. Cox, K. 2014. Invasive plant legislation, Glendoick website: www.glendoick.com/Invasive-Plant-Legislation. Milne, R.I. 2017. Rhododendron. Reaktion Books (Botanical

Series). Milne, R.I. & Abbott, R.J. 2000. Origin and evolution of invasive naturalized material of Rhododendron ponticum L. in the British Isles. Molecular Ecology 9: 541–56. Pearman, D., Bennallick, I., & Edwards, B. 2019. The impact of native and alien ‘thugs’ in semi-natural habitats. BSBI

News 142: 6–11.

Dr Richard Milne

Institute of Molecular Plant Sciences, School of Biology, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JH

R.Milne@ed.ac.uk

A new identity for a naturalised Chilean Oxalis

JULIAN SHAW

Oxalis attracts many monikers, some of them unprintable. One amusing epithet I came cross was Julian Sutton’s ‘Weeds-R-Us’ when he was skilfully writing witty sales talk for an Oxalis in his nursery catalogue days. Those of us who have grown what was believed to be Oxalis megalorrhiza in a greenhouse would likely agree that was an apposite label. However, it transpires that Oxalis mirbelii Dehnhardt (1839) is the earliest available name for Oxalis megalorrhiza sensu Dandy & Young (1959), a succulent Oxalis that is widely cultivated as a curiosity, a greenhouse alien, and naturalised in the Isles of Scilly (Lousley, 1971; Parslow & Bennallick, 2017; Stace, 2019) where it was said to be introduced in 1894 (King, 1985). Records show a large consignment of assorted succulent plants was received at Tresco Abbey Gardens from Kew on 12 April 1894, perhaps this Oxalis ‘carnosa’ as it was then known, was amongst them. However, a painting dated 1879 by Fanny Dorrien Smith reproduced in King (1985: 71, painting no. 8) shows the plant as Oxalis crassifolia misapplied. pointing to a prior introduction. Perhaps the use of the pseudonym is responsible for the date of introduction confusion. There is an excellent modern delineation by Barbara Everard in Lousley’s Flora (1971, p. 251). Sometime after its arrival in Britain, Lindley (1827) and Hooker (1828) misidentified it as Oxalis carnosa Mol. Subsequently Dandy & Young (1959) misidentified it as O. megalorrhiza Jacq.

Recent collections from lomas vegetation (coastal vegetation sustained by fog) in southern Peru by a Kew team (Whaley et al., 2019) included plants with massive subterranean roots that match the drawing of a plant found there and illustrated in 1714 by French explorer Louis Feuillée. As this Oxalis was one of the plants in this publication that somehow was overlooked by Linnaeus, it fell to an Austrian botanist Nikolaus Joseph Jacquin to name Feuillée’s plant Oxalis megalorrhiza in his 1794 Oxalis monograph. This is quite distinct from the plant found in Valparaíso, Chile that was introduced to Britain by James McRae back in 1825.

Oxalis mirbelii belongs to section Carnosae, consisting of mostly locally endemic species distributed along the western coast of South America, from Chile to Ecuador and the Galapagos (Heibl & Renner, 2012). While the Chilean species have been the focus of many studies, comparatively little work has been done on those from Peru, which has been hampered by difficulty of access, paucity of material and loss of many types in the Berlin herbarium. Had better material from Peru been available at the time, it is unlikely Dandy & Young would have confused the two species concerned.

Alicia Lourteig’s (2000) monographic revision of South American Oxalis failed to notice this misidentification and consequently she included Peruvian material of Oxalis megalorrhiza within O.pachyrrhiza, but that is another story that does