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shows exactly the same distribution as the Sderanthus. 

 Only in very few places it has b'een found, which are 

 not situated near the présent or former river-beds of the 

 Rhine and Meuse. In Belgium it is less rare than the two 

 former species and particularly in the central part it has 

 been found several times. Yet it seems admissible to bring 

 its présence in the "Breckland-sands" (and in Surrey) in 

 connection with a former vicinity of the Rhine. Silène 

 conica is a noteworthy plant. If we only study its distri- 

 bution in Germany and in our country, we get entirely 

 the impression of having before us a river-plant. Garcke 

 records the following stations in Germany: the région of 

 the Rhine, specially the "Mainzerbecken", further the 

 région of the Nahe and the Moselle, and the Palatinate. 

 In Holland this species has been found on the Meuse, 

 Waal, Rhine, IJsel and the mouth of the Vecht (Naarden) 

 and in the dunes between Beverwijk and Terheiden. So 

 there seems to be no doubt concerning its character as a 

 river-plant ! Yet we hâve to be careful. In Belgium it 

 occurs namely particularly along the coast, which explains 

 at the same time a station near Kadzand in our country, 

 and the flora of Schinz and Keller for Switzerland 

 considers it to hâve been introduced from the mediîerra- 

 nean régions. Havc we got to do hère therefore with a 

 typical atlantic species? It is not impossible, but its distri- 

 bution along the Rhine and our big rivers, as well as the 

 big chasm between the stations Kadzand and Terheiden 

 are at any rate very striking phenomena. Are the Englisch 

 stations in Sussex and Kent perhaps based on a distribution 

 along the west-coast of Europe, those in Norfolk and 

 Suffolk on a distribution along the Rhine? Veronica tri- 

 phyllos, common in Germany, with the exception of the 

 north-west part and Sleswick, fairly common also in the 

 central part of Belgium, is found in our country chiefly 

 along the rivers Meuse. Rhine, Ysel, Eem, Vecht and 



