Eleocharis austriaca Hayek [syn.: E. mamillata (H. Lindb.) H. Lindb. subsp. austriaca (Hayek) Strandh., E. palustris subsp. austriaca (Hayek) Podp., E. leptostylopodiata Zinserl.] (Eur.) – Discovered in 2006 in several places in a military base in Elsenborn, along with Eleocharis obtusa (Lambinon & Mause 2010). It grows along muddy tracks and seems to be very well established. Residence status of Eleocharis austriaca in Belgium is uncertain: the species might as well be native (recent extension of its natural distribution range) or non-native. At least at present, its presence seems to be closely associated with military activities, as is the case in a recently discovered location in nearby Germany (Mause 2007). The presence of the American Eleocharis obtusa in the same campsite possibly rather suggests an accidental introduction (see also sub Scirpus atrovirens). Therefore, Eleocharis austriaca should be looked for in similar habitats outside the military base. For the time being, and although native status cannot be excluded, it is considered to be a non-native species in Belgium. Eleocharis austriaca is an enigmatic species. It is present in large parts of Europe, from northern Norway to northern Spain and from the British Isles to the Ural. It was not found in the British Isles until 1947 (Walters 1963) and elsewhere in Europe it is definitely increasing lately (although it is not clear whether Eleocharis austriaca is really in progress or whether it is simply better distinguished nowadays).
A closer examination of Belgian populations of Eleocharis palustris, at least those in the surroundings of Elsenborn, might yield additional records.
Eleocharis austriaca
Eleocharis palustris
Selected literature
Corner R.W.M. (1975) Eleocharis austriaca Hayek new to Scotland. Watsonia 10: 411-419.
Galen Smith S. & Gregor T. (2014) North American distribution of Eleocharis mamillata (Cyperaceae) and confusion with E. macrostachya and E. palustris. Rhodora 116 (966): 163-186. [available online at: http://rhodorajournal.org/doi/abs/10.3119/13-14]
Galunder R. & Patzke E. (1989) Über die Verbreitung von Eleocharis austriaca Hayek und Eleocharis mammilata Lindb. f. im Bergischen Land und in den Randgebieten. Flor. Rundbr. 23(1): 1-5.
Gregor T. (2003) Eleocharis mamillata – distribution and infraspecific differentation. Folia Geobot. 38: 49-64.
Gregor T. & Barth U. (1998) Die Weichstengelige Sumpfbinse Eleocharis mamillata in Hessen. Natur und Museum 128(4): 113-124.
Lambinon J. & Mause R. (2010) Deux Eleocharis (Cyperaceae) nouveaux pour la flore belge: E. austriaca et E. obtusa au Camp d’Elsenborn (Haute-Ardenne). Dumortiera 98: 1-5.
Mause R. (2007) Eleocharis austriaca im Nationalpark Eifel und weitere seltene und bemerkenswerte Pflanzenfunde aus dem Kreis Düren und der Nordeifel. Decheniana 160: 91-93.
Saintenoy-Simon J. (2017) Excursion de l'A.E.F. à Elsenborn, le 30 juillet 2016. Adoxa 92: 37-40.
Strandhede S.-O. (1966) Morphologic variation and taxonomy in European Eleocharis subser. Palustres. Opera Bot. 10(2): 1-187.
Šturm R. & Bačič T. (2013) Eleocharis palustris group (Eleocharis R. Br. subser. Eleocharis) in Slovenia: revision in herbarium LJU (in Slovenian). Hladnikia 31: 11-30. [available online at: http://bds.biologija.org/gradiva/hladnikia/online_issue/HLADNIKIA_31_str_11-30.pdf]
Walters S.M. (1953) Heleocharis mamillata Lindb. fil. and allied species. Ber. Schweiz. Bot. Ges. 63: 271-286.
Walters S.M. (1963) Eleocharis austriaca Hayek, a species new to the British Isles. Watsonia 5(6): 329-335.
Wolff P. & Korneck D. (1984) Die Österreichische Sumpfbinse (Eleocharis austriaca Hayek) in der “Wahner Heide”. Tuexenia 4: 45-48.