Over standplaats en voorkomen van Poa bulbosa L. var. bulbosa en var. vivipara Koeler in Nederland, in het bijzonder in de duinstreek

Poa bulbosa, which according to Sukopp & Scholz (1968) must be considered an archaeophytic species in Central Europe, appears to be a neophytic species in the Netherlands. It was recorded there with certainty for the first time in 1835. In the cooler parts of Europe P. bulbosa is nearly always proliferous (var. vivipara). However, most populations in the Dutch dunes are non-proliferous, as they are in England (var. bulbosa). From about 1900 onwards, var. bulbosa extended its area in the Netherlands. Today it is rather widespread in the dunes, especially near sea villages (fig. 1). P. bulbusa var. vivipara has been recorded incidentally as an adventitious plant, but has also settled locally in the Fluviatile and Dune districts (fig. 2). Both forms occur in the same habitats. Most of these are treaded grassy sites on dunesand, often with some kind of support from organic material (e.g. dung). Near Haarlem both forms are found at the feet of Fagus sylvatica trees. Both types of habitat are obviously influenced by men, like those of most neophytic species. As to the plant communities in which it occurs apart from the habitat near tree feet the species is characteristic of dry sandy (pioneer) grassland (Koelerio-Corynephoretea) rather than of dry ruderal vegetations (Sisymbrietalia). In particular it often occurs in facies in the Tortulo-Phleetum, and also in Thero-Airion-like vegetations.