2. Echinochloa crus-galli (L.) Beauv. (Eurasia) – Now a very common alien, already known in Belgium long before 1800 (Verloove 2006). According to some sources it possibly is an archaeophyte in parts of western and Central Europe (Conert 1998, Hoste 2006a). However, Echinochloa crus-galli surely long remained rather rare and ephemeral in Belgium. Its wider naturalisation roughly coincides with the massive cultivation of maize, especially in parts of Flanders and probably dates back to the 1970’s. In a short while Echinochloa crus-galli has become one of the commonest species in Flanders (see distribution map in Hoste l.c.). It has always been much scarcer in Wallonia (compare with map in van Rompaey & Delvosalle 1979). Echinochloa crus-galli is still commonly introduced, mainly with cereals (formerly also with wool).
Echinochloa crus-galli is an exceedingly variable species in terms of awn length (ranging from absent to very long), habitat (from small and decumbent to erect and very tall), spikelet length,… (see for instance Shouliang & Phillips 2006). The taxonomic significance of this variation on a worldwide scale appears to be limited. Part of this variation has reliably been reported from Belgium as well. Plants (often dwarf) with small, densely clustered, pale greenish spikelets have been ascribed to subsp. spiralis (Vasing.) Tsvelev (syn.: E. occidentalis (Wiegand) Rydb.; see Tsvelev 1984, Scholz 2002) and were recently collected, for instance, on muddy banks of exposed fishponds near Zonhoven (det. H. Scholz). However, Shouliang & Phillips l.c. give a rather aberrant circumscription of their var. mitis (Purh) Petermann, a synonym of subsp. spiralis (robust, erect plants with large and stiff inflorescences). Perhaps a more distinct variation represents var. praticola Ohwi, a weed from southeast Asia that, in general habit, more looks like a vigorous form of Echinochloa colona, especially on behalf of its small, regularly arranged spikelets. It otherwise seems to be more close to Echinochloa crus-galli (presence of bristles on inflorescence branches, wider leaves, shorter lower glumes, colour of caryopsis, etc.). This variety appears to be strictly ephemeral in Belgium but might have been overlooked. It has been reliably recorded in the past years, for instance, in the port of Antwerpen: unloading quay of the Vamo Mills grain mill by the Albertkanaal in 1994 and unloading quay of the Cargill plant by the Kanaaldok in 2003, twice obviously associated with grain importation.
Selected literature:
Conert H.J. (ed.) (1998) Gustav Hegi Illustrierte Flora von Mitteleuropa. Band I, Teil 3 Poaceae (3.Auflage). Parey Buchverlag, Berlin: XXVII + 898 p.
Hoste I. (2006a) Echinochloa crus-galli. In: Van Landuyt W., Hoste I., Vanhecke L., Van den Bremt P., Vercruysse W. & De Beer D., Atlas van de flora van Vlaanderen en het Brussels gewest. Instituut voor Natuur- en Bosonderzoek, Nationale Plantentuin van België en Flo.Wer: 353.
Scholz H. (2002) Wenig bekannte heimische und fremdländische Gräser Deutschlands. Flor. Rundbr. 36(1-2): 33-44.
Shouliang C. & Phillips S.M. (2006) Echinochloa. In: Zhengyi W. & Raven, P.H. (eds.), Flora of China, vol. 22: 515-518. Science Press, Beijing & Missouri Botanical Garden Press, St. Louis.
Tsvelev N.N. (1984) Grasses of the Soviet Union, part 1 and 2. A.A. Balkema, Rotterdam: XVI + 1196 p.
Van Rompaey E. & Delvosalle L. (1979) Atlas van de Belgische en Luxemburgse flora, Pteridofyten en spermatofyten. 2e editie. Nationale Plantentuin van België, Meise (1542 kaartjes).
Verloove F. (2006) Catalogue of neophytes in Belgium. Scripta Botanica Belgica 39: 89 p.