Leersia oryzoides (L.) Swartz (Rijstgras) in het winterbed van de Maas

While monitoring riverbank vegetation, Leersia oryzoides was recorded this year in eleven 1 kmsquares in inundation area’s along the river Meuse. In 1994 and 1995 this grass was also observed at several new locations in the valley of this river in the Province Limburg.²³4 The supposition that the decline of this species is less severe than assumed² is confirmed by these new findings. In some 1 km-squares at the lower course of the river where L. oryzoides was last recorded before 1950, it appeared to be still present along ditches. Probably L. oryzoides is less abundant than before 1950 and therefore overlooked. In the Province Limburg new suitable habitats for L. oryzoides were created due to gravel production. In this Province it is mostly found in open initial vegetations on shallow silty margins of lakes formed after gravel extraction. Leersia oryzoides is seldom found here at more natural sites like riverbanks.