Limnanthes douglasii R. Brown (southwestern U.S.A.) – A very rare and mostly ephemeral escape from (or relic of?) cultivation. Probably first documented from a park in Roeselare where Limnanthes douglasii was recorded in abundance under shrubs in 1994. In the past years also observed in Baudour (2013) and Moorslede (2014), in the latter locality on the exposed margins of a recently created pond.
Limnanthes douglasii is a relatively rare alien in Europe and often remains strictly casual, except perhaps in parts of the British Isles (e.g. Clement 1978, Clement & Foster 1994). It is also known from Sweden (Karlsson 2002).
Limnanthes douglasii is a highly polymorphic species. In North America five subspecies are currently recognized (Morin 2010) and its delimitation is still uncertain (see also Meyers 2010). The exact placement of plants in cultivation is critical; most belong to cultivars of uncertain origin (e.g. ‘Grandiflora’, ‘Sulphurea’, ‘Nivea’ and ‘Rosea’; see King 1997, Jäger & al. 2008).
Selected literature:
Buchner R., Halbritter H., Pfundner G. & Hesse M. (1990) Pollen of Limnanthes douglasii: a reinvestigation. Grana 29(3): 207-211. [available online at: http://www.tandfonline.com/doi/pdf/10.1080/00173139009427753]
Clement E.J. (1978) Adventive News 11. Mixed bag. BSBI News 19: 12-17. [available online at: http://archive.bsbi.org.uk/BSBINews19.pdf]
Clement E.J. & Foster M.C. (1994) Alien plants of the British Isles. BSBI, London: XVIII + 590 p.
Hofmann U. & Ludewig J. (1985) Morphologie und systematische Stellung von Limnanthes douglasii R. Brown, einem repräsentativen Vertreter der Limnanthaceae. Bot. Jahrb. 105(3): 401-431.
Huynh K.L. (1971) The morphological development of the pollen of Limnanthes douglasii (Limnanthaceae). Grana 11(1): 58-61. [available online at: http://www.tandfonline.com/doi/pdf/10.1080/00173137109427413]
Huynh K-L. (1982) Le pollen du Limnanthes douglasii (Limnanthaceae) en microscopie électronique. Pollen Spores 24(2): 211-234.
Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.
Karlsson T. (2002) Nyheter i den svenska kärlväxtfloraen II. Korsblommiga-flockblommiga. Svensk Bot. Tidskr. 96(3-4): 186-206. [available online at: http://svenskbotanik.se/wp-content/uploads/2013/10/Karlsson5.pdf]
King C.J. (1997) Limnanthes. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 5. Cambridge University Press, Cambridge: 17.
Meyers S.C. (2010) Evolutionary Relationships and an Investigation of Sympatric Speciation within Limnanthaceae. PhD dissertation, Oregon State University [available online at: http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/16166/Stephen_Meyers_PhDthesis.pdf?sequence=1]
Morin N.R. (2010) Limnanthus. In: Flora of North America Editorial Committee (eds.), Flora of North America, vol. 7. Oxford University Press, New York-Oxford: 173-183. [available online at: http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=118578]
Sell P. & Murrell G. (2009) Flora of Great Britain and Ireland. Vol. 3 Mimosaceae – Lentibulariaceae. Cambridge University Press, Cambridge: XXVIII + 595 p.