Cotula coronopifolia L. (S-Afr., Aus.) – A rare, locally more or less naturalised alien. Formerly recorded as an ephemeral wool alien in the Vesdre valley, at least between 1895 and 1947. In the past years increasingly observed, usually in saline, temporarily wet habitats (Verloove & al. 2004). Known since 2001 from the nature reserve Uitkerkse Polder near Blankenberge and since 2002 from several sand raised sites in the port of Antwerpen (Waaslandhaven). Since 2009 also known from the port-area in Zeebrugge (Hoge Noen), furthermore from Knokke and Oudenburg. Other recent records, for instance in Menen and Zonhoven, are apparently merely ephemeral. In Uitkerke Cotula coronopifolia is in expansion and by now covers a large area. It has also spread to several adjacent areas, one of which is more than 2 km away from the original locality (pers. comm. D. Content). A similar local expansion has also been in observed in the Waaslandhaven.
Cotula coronopifolia is probably introduced by migrating waterfowl. In the past decades it is slowly spreading in neighbouring territories as well, for instance in the Netherlands and in the British Isles (see for instance Van der Toorn 1980, Clement 1993).
This species belongs to a taxonomically complex group (Powell & al. 2014). The widespread weedy species is C. coronopifolia s.str.
Selected literature:
Clement E.J. (1993) Buttonweed (Cotula coronopifolia L.), new to S. Hants (v.c. 11). BSBI News 64: 43-46.
Corillion R. & Lollierou C. (1958) Sur l'extension récente et les caractères des végétations à Cotula coronopifolia L. (Composées) des rives du Trieux. Bull. Soc. Sci. Bretagne 31: 102-106.
Marchioni A. (1972) Sulla presenza in Sardegna di Cotula coronopifolia L. Ann. Bot. 29: 179-182.
Martin J. (1993) Cotula coronopifolia established in Yorkshire. BSBI News 64: 42-43.
Mohr A. (1999) Laugenblume Cotula coronopifolia - Erstnachweis für Mecklenburg-Vorpommern. Bot. Rundbr. Mecklenburg-Vorpommern 33: 129-130.
Powell R.F., Boatwright J.S. & Magee A.R. (2014) A taxonomic revision of the Cotula coronopifolia group (Asteraceae) and implications for the conservation statuses of the species. South African Journal of Botany 93: 105–117. [available online at: https://www.sciencedirect.com/science/article/pii/S0254629914000507]
Van der Toorn J. (1980) On the ecology of Cotula coronopifolia L. and Ranunculus sceleratus L.: 1. Geographic distribution, habitat, and field observations. Acta Bot. Neerl. 29(5/6): 385-396.
Verloove F., Zwaenepoel A. & Piesschaert F. (2004) Omtrent enkele recente vondsten van Cotula coronopifolia in België en aangrenzend Noord-Frankrijk. Dumortiera 83: 1-4.
Willment D. (1994) More on Cotula coronopifolia. BSBI News 65: 38-39.