Malva trimestris
Malva trimestris (L.) Salisb. (syn.: Lavatera trimestris L., Stegia trimestris (L.) Risso) (Medit.) – A rather rare and ephemeral garden escape, known since 1941. Most records are from dumps or road verges.
Malva trimestris is a rather variable species. Petals are usually pinkish but white-flowered variants are frequent in cultivation and have been recorded as an escape. Taxonomically more important is the distinction of a form that mostly looks like var. brachypoda (Pérez Lara) Verloove et Lambinon (see Verloove & Lambinon 2011). It is distinguished from var. trimestris in the following couplet:
- Pedicels and peduncles with appressed stellate hairs === var. brachypoda
- Pedicels and peduncles with simple, patent to retrorse bristle-like hairs === var. trimestris
Such plants fail to key out in many floras since Malva trimestris is usually accepted as a species with simple or few-rayed hairs (see for instance Fernandes 1968). However, they do not fully correspond with var. brachypoda neither since trichome branches are not fully adpressed to the pedicel or peduncle (compare with Fernandes 1993: "(...) pelos estrellados (...) ramas delgadas y aplicadas en toda su extensión"). Plants found with these characters obviously are of ornamental origin. They most likely represent hybrids or cultivars of uncertain parentage/origin.
Both varieties have been recorded in Belgium, var. trimestris being the usual garden plant. Cf. var. brachypoda was found in 1977 in Grand-Halleux (dump), in 1982 in Zuienkerke (road verge), in 2006 in Rumbeke (dump) and in 2012 by a disused railway track in Gistel.
Loos (2010) proposed the new combination Malva trimestris (L.) G.H. Loos but this binomial is superfluous since it was already validated much earlier by Salisbury in 1796.
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Malva trimestris var. trimestris |
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Malva trimestris var. brachypoda |
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Selected literature:
Fernandes R.B. (1968) Contribuçoes para o conhecimento do género Lavatera L. I. Notas sobre algumas espécies. Collectanea Botanica 7: 393-448.
Fernandes R. (1968) Lavatera. In: Tutin T.G. & al. (eds.), Flora Europaea, volume 2. Cambridge University Press, Cambridge: 251-253.
Iamonico D. (2017) Nomenclatural notes on some annual mallows (Malvaceae). Acta Bot. Croatica (in press).
Loos G.H. (2010) Taxonomische Neukombinationen zur Flora Mittel- und Osteuropas, insbesondere Nordrhein-Westfalens. Online-Veröff. Bochumer Bot. Ver. 2(1): 1-20.
Fernandes R. (1993) Lavatera L. In: Castroviejo S. & al. (eds.), Flora Iberica, Vol. 3. Madrid: Real Jardín Botánico-CSIC: 232-243.
Verloove F. & Lambinon J. (2011) The non-native vascular flora of Belgium: new names and combinations. New Journ. Bot. 1(1): 38-42.