108 



P. F. YEO 



advice on microscopical technique and by drawing my attention to the triacetin method 

 and by Dr. J. R. S. Fincham, who inspected some of my preparations and assisted with 

 their interpretation. 



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LOVE, a. & D., 1948, Chromosome numbers of Northern Plant Species, Reykjavik. 

 MAUDE, P. F., 1939, The Merton Catalogue, New Phytol, 38, 1-31. 



PUGSLEY, H. W., 1930, A Revision of the British Euphrasiae, J. Linn. Soc. Lond. Bot., 48, 467-544. 



, 1936, Enumeration of the Species of Euphrasia L. Sect. Semicalcaratae Benth., /. Bot. 



74, 273-288. 



TISCHLER, G., 1950, Die Chromosomenzahlen der Gefdsspflanzen Mitteleuropas ; 's Gravenhage. 

 WITSCH, H. VON, 1932, Chromosomenstudien an mitteleuropaischen Rhinantheen, Oesterr. Bot. Zeitschr. 

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