By comparing a recent inventory of Viscum album L. (De Graaf 1980) with older data, it appeared that the number of provenances in The Netherlands has decreased drastically in recent years. However, the methods usually applied by Dutch botanists to determine the degree of this decline appears to be inadequate. This follows from a comparison of distribution maps based on different grid widths. Analysis of the habitats of Viscum supports the surmise that the phytogeographical Chalk and Loess Districts cf. Van Soest (1929, 1977) should be rejoined into one Centreuropean District (cf. Van Soest 1925).