336 



the ancient Rhine-bed of Van Eeden. The importance of 

 this species to our problem seems to me to be the same 

 as the one of Holosteum umbellatum. Finally as to the last 

 species, which hâve to be treated, Phleum Boehmeri and 

 Muscari racemosum, I think them very valuable again. 

 Phleum Boehmeri is a species of a barren hilly soil in 

 Central Europe, not found in north-west Germany and 

 Sleswick-Holstein ; in Belgium it is rare and occurs in the 

 east part only. In our country it has been found on the 

 Meuse near Rotterdam, near Leiden and Harlem. It seems 

 to me, that the stations in the "Breckland-area" and in 

 the counties of Bedfordshire, Hertfordshire and Essex im- 

 mediately to the south-west of it surely point to the 

 Rhine as their cause. Muscari racemosum does not occur 

 in Holland, neither in Belgium, but in south and central 

 Germany it is a rather common species. Apparently the 

 plants of the "Breckland-area" — in Great Britain the species 

 has been recorded outside but not far outside Breckland 

 proper on chalky grassland — form a far advanced out- 

 post of the main mass in Central Europe. And as our 

 Muscari is a species of a hot soil, quite as the Artemisia 

 campestris, it might be assumed that it has corne to England 

 together with this plant and in the same way. 



For the moment I must confine myself to thèse com- 

 munications. I think however, that it was worth while to 

 make them and that they may be said at any rate to form 

 a contribution to the problem of the course of the Rhine 

 through England as v/ell as to our knowîedge of the origin 

 of the British flora. Perhaps one of the younger ones 

 amongst us cares to work this subject further out ! Finally a 

 well-nigh superflous encouragement to ail readers, to be as 

 accurate as possible when recording stations in herbaria etc. ! 

 We hâve seen, v.'hich important problems may be brought 

 nearer to their solution by many reliable floristicaî data ! 



Amsterdam, November 1923. 



^^ 



