2 -'p- r^ -.;:.: u Us *4 ^J of ^« 



^'. HoMMA and Mr. S. Imai for tlicir kind atlvicc and constant encouragement. 

 The writer is also indebted to ] )r. A. \\' . IIknkv, pathologist, University Farm, 

 University of Minnesota, St. Paul, Minn.; Mr. T,. II. Dkwev, botanist in Charge 

 of ]''iber Investigations, U. S. DeiJartnient of Agriculture, Washington ; Mr. R. 

 I.. I ).\\is, plant-breeder, U. S. Ucpartmenl of Agriculture, Washington; Miss 

 lIici.EN II.VKT, University I'arni, University of Minne.sota, St. Paul, Minn, and 

 to Messrs. T. Akino and \'. S.axto, e.xperts of the Teikoku Seima Kaisha for 

 their kindness in sending us many valuable specimens and papers. 



II. Historical Review of the Flax Rust. 



The rust of flax caused by Mclaiiipsora was first de.scribed by C. H. Pi;k- 

 soon'^ in I. So I as I'redo ininiata Pr:K.s. var. Lint Picks. Important studies were 

 made by J. C. Aktiiük-\ F. D. FK()MMir\ A. Huciiiikim^"', F. Köknicke"'^ F. 

 Tonr.ER"\ A. W. Hknkv'', H. Hakt^' and others. 



In Europe, Buciiiihim" reported in 1912 on the specialization betweea 

 Mclanipsora parasitic on liifferent species of Liiiuni. G. H. Pethybkidge and 

 H. A. I.aeferty"-' published in 1920 a detailed report on the flax rust. In the 

 neNt year, Toi;iek''' reported especially the anatomical study of the afiected 

 tissues of the host plant. In 1923, J. C. Dokst'"^ was successful in selecting 

 a rust resistant variety from the P'risian flax. 



In North America, Arthur^' first proved the autoecious formation of the 

 aecidium in 1906, and Fromme"^ reported on physiological and cytological studies 

 of the fiuigns in 191 2. Recently, Hart"^ also has made studies concerning the 

 pli\siology^ of the fungus. In 1925, Henry* reported that there are se\eral 



I) .Synopsis methodica fungorum, p. 216 (1801^. 



2; Jour, of Myc. XIII, p. 201-202 (1907J. 



J) Bull. Torr. Bot. Club, X.XXIX. p. 113-131 (1912). 



4) Ber. lleutsch. bot. Ges. XXXIII, p. 73-75 (igi5). 



5) Land- u. Forstw. Zeit. Preussen (1865), p. 42 (1865). 

 fi) Faserforsch. I, p. 223-229 (1921). 



7) riiytopatli. XV, p. 52 (1925). 



8) Pliytopath. XV, p. 52-53 (1925); Il-id. XVI, p. 1S5-205 (1926). 



y) jour. Kept. Agric. \: 'rcclin. Instr. Irel.-uid, XX, p. 334-337 (1920). 

 10} Kept. Internat. Conf. Pliytopath. & Econ. Entomol. Holland (1U23J, p. 33-34 (1924). 



