Diplachne fusca (L.) P. Beauv. ex Roem. & Schult. subsp. fascicularis (Lam.) P.M. Peterson & N. Snow (syn.: D. fascicularis (Lam.) P. Beauv., D. fusca var. fascicularis (Lam.) P.M. Peterson & N. Snow, Leptochloa fascicularis (Lam.) A. Gray, L. fusca (L.) Kunth subsp. fascicularis (Lam.) N. Snow) (Am., grain and wool alien) – A very rare and ephemeral alien. Formerly recorded as wool alien in the valley of river Vesdre near Verviers, at least between 1831 and 1947 (Verloove 2006). In 2016 a single individual was seen at the Amerikadok in the Antwerp port area. It grew along with other weeds that were obviously introduced with rice: Ammannia coccinea, Dactyloctenium aegyptium, Echinochloa oryzicola, Leersia oryzoides, Paspalum distichum, etc. Diplachne fusca subsp. fascicularis is a reputed weed in rice field weeds, also in southern Europe (e.g. Del Monte & Cortés 2000, Romani & Tabacchi 2000, Pérez Chiscano & al. 2010, Osca 2013).
Diplachne fascicularis is rather easily distinguished from D. uninervia and D. fusca s. str. in Belgium. However, on a global scale these taxa more or less overlap and have been accommodated in a collective taxon (D. fusca) by Snow (1998). Molecular data (e.g. Peterson & al. 2015) confirm that there are very few genetic differences between the subspecies of D. fusca.
Selected literature
Del Monte J.P. & Cortés J.A. (2000) Acerca de las especies del género Leptochloa, como malas hierbas de los arrozales y su distribución en España. Bol. San. Veg. Plagas 26: 599-604. [available online at: http://www.magrama.gob.es/ministerio/pags/biblioteca/plagas/BSVP-26-04-5...
Osca J.M. (2013) Expansion of Leptochloa fusca ssp. uninervia and Leptochloa fusca ssp. fascicularis in rice fields in Valencia, eastern Spain. Weed Research 53(6): 479-488.
Pérez Chiscano J.L., Snow N. & Sánchez Guillón E. (2010) Comentario sobre el género Leptochloa P. Beauv. (Poaceae, Eragrostideae) en Extremadura y Andalucía (España). Acta botánica malacitana 35: 189-192. [available online at: http://www.biolveg.uma.es/abm/Volumenes/vol35/35_PerezChiscano.pdf]
Peterson P.M., Romaschenko K. & Arrieta Y.H. (2015) A molecular phylogeny and classification of the Eleusininae with a new genus, Micrachne (Poaceae: Chloridoideae: Cynodonteae). Taxon 64(3): 445-467. [available online at: https://www.researchgate.net/publication/271851457_A_molecular_phylogeny...
Romani M. & Tabacchi M. (2000) Leptochloa fascicularis nuova infestante del riso. L’Informatore Agrario 36: 65-66.
Snow N. (1998) Nomenclatural changes in Leptochloa P. Beauvois sensu lato (Poaceae, Chloridoideae). Novon 8: 77-80.
Verloove F. (2006) Catalogue of neophytes in Belgium (1800-2005). Scripta Botanica Belgica 39: 89 p. [available online at: http://alienplantsbelgium.be/sites/alienplantsbelgium.be/files/tabel_2.pdf]