2. Spartina townsendii H. et J. Groves (= Spartina alterniflora Loisel. x S. maritima (Curt.) Fernald; incl. S. anglica C.E. Hubbard) (hybr.) – A very locally naturalised and invasive hybridogenous species, derived from a North American and European species. Only found in the maritime district, the number of suitable habitats being restricted to the estuary of river Schelde and some coastal areas. Most locations are confined to nature reserves or other more or less protected areas. Deliberately introduced in 1924 for tideland reclamation and first reported as an escape in 1938 (Matagne 1943). By now, Spartina townsendii has completely displaced native Spartina maritima. Maquet (1982) provides an overview of its distribution in Belgium.
Spartina townsendii is treated here in a broad sense, including S. anglica (syn.: S. townsendii var. anglica (C.E. Hubbard) Lambinon et Maquet). The latter is believed to be a naturally formed amphidiploid (a fertile tetraploid), derived from Spartina townsendii. It is often treated at specific rank (see for instance Barkworth 2003, Stace 2010) but is linked through intermediates with Spartina townsendii. Both are claimed for Belgium but this needs confirmation. They are distinguished as follows:
- Anthers well-filled and dehiscent at maturity, up to 10(-13) mm long. Ligule usually (1-)2(-3) mm long. Plant often tall === var. anglica
- Anthers poorly-filled and indehiscent at maturity, up to 6-7 mm long. Ligule usually at most 1 mm long. Plant often less tall === var. townsendii
The often problematic distinction between the infraspecific taxa of Spartina townsendii and S. maritima is further complicated by severely damaged plant material. For instance, ligules are often severely damaged by tidal flow or mud and its characteristics hard to assess (see also Trist 1998).
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Selected literature:
Barkworth M.E. (2003) Spartina. In: Barkworth M.E. & al. (eds.), Flora of North America north of Mexico, vol. 25: 240-251. Oxford University Press, New York-Oxford.
Chung M.G. (2001) The decline of Spartina alterniflora (Poaceae) in the British Isles. Watsonia 23: 391-400.
Drok W.J.A. (1983) Is Spartina anglica Hubbard wel een goede soort? Gorteria 11: 243-252.
Fustec-Mathon E. & Lahondère C. (1974) Répartition des Spartines, espèces colonisatrices des vases salées, entre Loire et Gironde. Bull. Soc. Bot. France 121: 113-122.
Goodman P.J., Braybrooks E.M. & Lambert J.M. (1959) Investigations into 'die-back' in Spartina townsendii agg. 1. The present status of Spartina townsendii in Britain. J. Ecol. 47: 651-677.
Goodman P.J., Braybrooks E.M., Lambert J.M. & Marchant C.J. (1969) Spartina Schreb., in Biological Flora of the British Isles. J. Ecol. 57: 285-313.
Guenegou M.-C. & Levasseur J.-E. (1992) Le genre Spartina en Bretagne. Bull. Soc. Bot. Centre-Ouest n.s. 23: 35-38.
Hubbard J.C.E. (1965) Spartina marshes in southern England, 6. Pattern of invasion in Poole Harbour. J. Ecol. 53: 799-813.
Maquet Ph. (1982) Morphologie, taxonomie et distribution de Spartina townsendii H. & J. Groves s.l. (Poaceae) en Belgique et dans les régions voisines. Bull. Soc. Roy. Bot. Belgique 115: 198-208.
Marchant C.J. (1967) Evoultion in Spartina (Graminae), 1. The history and morphology of the genus in Britain. Bot. J. Linn. Soc. 60: 1-24.
Matagne H. (1943) Quelques phanérogames nouvelles pour la flore belge. Bull. Soc. Roy. Bot. Belg. 75: 123-131.
Stace C. (2010) New flora of the British Isles, 3th ed.: XXXII + 1232 p. Cambridge University Press.
Trist P.J.O. (1998) Spartina. In: Rich T.C.G. & Jermy A.C. (eds.), Plant crib: 370. BSBI, London.
Vanhecke L. (2006b) Spartina townsendii. 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: 848-849.
Van Schreven A.C. (1958) Kiem-en Kweekproeven met Spartina townsendii Groves. Acta Bot. Neerl. 7: 205-216.