Taraxacum limnanthes Haglund subsp. limnanthoides Van Soest op Schiermonnikoog

Taraxacum limnanthes was described by HAGLUND (1946). VAN SOEST (1965) distinguishes two subspecies. One of these, subsp. limnanthoides, occurs in the Netherlands. In this country it is found on the Wadden Islands, near the IJssel Lake (the former Zuiderzee), and in Zeeland. The present paper is concerned with investigations on Schiermonnikoog (one of the Wadden Islands). Here T. limnanthes subsp. limnanthoides occurs in an area with a west to east salt gradient. The habitat of maximum abundance consists of moist dune valleys characterized by a peaty soil. The soil water, which is practically fresh, has a strongly fluctuating level. The adjacent salt marshes which are periodically inundated by the sea show a lower density of the species. T. limnanthes subsp. limnanthoides is generally found in vegetations belonging to the association complex Schoenetum nigricantis. It occurs less frequently in vegetations belonging to the alliance Loto-Trifolion, comprising associations which are mainly determined by fluctuating salinity conditions.