Louseworts are all semi-parasites. They steal nutrients and water from their neighbors. One used to believe that livestock were infested with louse when they ate these plants, which explains the name. The only two lousewort species found in the lowlands of Northwestern Europe are the common and marsh lousewort. Both species form winter buds. Their seeds do not have a long lifespan. While common lousewort seeds can wait up to two years to germinate, marsh lousewort seeds hardly last longer than one season. There are many more species of lousewort found in the mountains and tundra in the far north.