 The species favours lowland areas that are seasonally wet but never inundated , such as the margins of swamps and marshes . For example , in the Yule Brook Botany Reserve , where parallel sand ridges cross a clay flat , B. telmatiaea occurs neither in the lowest parts of the flat , where seasonal inundation occurs ; nor on the tops of the ridges , where the drainage is good ; but it is one of the most abundant plants of intermediate habitats , on ridge slopes and in higher areas of the clay flat . 
