Symphyotrichum novi-belgii
Symphyotrichum novi-belgii (L.) Nesom (syn.: Aster novi-belgii L.) (N-Am.) – A very rare, locally naturalized alien. This species is poorly known and requires further study. It may have been more widespread in the past but is now widely replaced by the taller and more vigorous S. xversicolor, its hybrid with S. laeve. Hoffman (1995) confirms that in Europe cultivated plants of Symphyotrichum novi-belgii (and doubtlessly wild ones too) are in fact mostly hybrids. They were referred to as “Aster novi-belgii Group” by Hetterscheid & van den Berg (1996). Persistent populations are known from a railway bank in Gent (Burggravenlaan), at least since 1985. Recently also confirmed in coastal dunes in Nieuwpoort and from a former railway siding near Torhout.
Leaves of Symphyotrichum novi-belgii are often said to be 7-10x as long as wide but this is not always the case. With its often lanceolate leaves, it sometimes looks like Symphyotrichum lanceolatum. However, in the latter involucral bracts are distinctly unequal, with a narrow green median part and tightly appressed while they are subequal, greener and loose in Symphyotrichum novi-belgii.
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Selected literature:
Hetterscheid W.L.A. & van den Berg R.G. (1996) Cultonomy of Aster L. Acta Bot. Neerl. 45(2): 173-181.
Hoffman M.H.A. (1995) Aster (1). Dendroflora 32: 6-23.
Jedlicka J. & Prach K. (2006) A comparison of two North-American asters invading in central Europe. Flora - Morphology, Distribution, Functional Ecology of Plants 201(8): 652-657.
Labrecque J. & Brouillet L. (1989) Biosystematic study of the Aster novi-belgii L. complex in Quebec. Amer. J. Bot. 76(6) suppl.: 252-253.
Labrecque J. & Brouillet L. (1996) Biosystematique du complexe de l'Aster novi-belgii (Asteraceae : Astereae) au Québec. Canad. J. Bot. 74: 162-188.
Marković M. & Popović M. (2010) Invasive perennial species Aster novi-belgii L. in the Belgrade area. Scientific Congress “Future with forests”. Belgrade, 11-13 November 2010 [available online at: http://congress.sfb.bg.ac.rs/PDF/landscape/rad13l.pdf]