102 The Plant World. 



where Trichodesmwm prevails. Quantitatively the Canary 

 Islands and the North Equatorial Current surpass the Sargasso 

 Sea and the branches of the Gulf Stream. — V. M. Spalding. 



Distribution of Hieracium. — Samuellson has recently 

 discussed * the forms of the Acroleucum group of the genus Hier- 

 acium, five in number, which occur in southeast Norway and 

 Sweden. The several forms occupy areas not distinctly separate, 

 and the group can not be broken up into smaller groups of re- 

 lated forms. Intermediate varieties do not occur even w^hen two 

 forms grow close together in the some habitat, and each form 

 exhibits a manifest "center of distribution" where it is most 

 numerously represented. The recent development of the form 

 is, according to the author the most important cause of the facts 

 of distribution recorded. Their areas of distribution are not 

 climatic areas. There are, however, various other forms of 

 Hieracium the areas of which are determined by climatic factor?. 

 It appears probable that most species of Hieracium have arisen 

 by mutation. — -V. M. Spalding. 



NOTES AND COMMENT. 



The first number of volume I of Phytopathology, the official 

 organ of the American Phytopathological Society, has been 

 received. It is published bi-monthly for the society at Ithaca, 

 New York, under the joint editorship of L. R. Jones, C. L. Shear, 

 and H. H. Whetzel, with a list of associate editors whose names 

 are well known in the annals of plant pathology as it has devel- 

 oped in America. It is well illustrated with half-tone plates 

 and zinc etchings, the press v/ork is excellent, and the list of con- 

 tributors a sufficient guaranty of the high character, both 

 scientific and literary, of the new journal. The subscription 

 price is $3.00 per year, subscriptions to be sent to Donald 

 Reddick, Business Manager, Ithaca, N. Y. 



Among the several papers which appear in this first issue 

 is one on "Crown Gall of Plants," by Erwin F. Smith. The 

 results recorded are the outcome of six years' work in the Bureau 

 of Plant Industrv on the part of the writer, with whom we are 

 associated Dr. C. O. Towhsend, Miss Nellie A. Brown, and Miss 

 Alice E. Haskins. The disease is conclusively shown to be due 



♦Samuclsson G., Uber die VerbreitunK einiger endemischer Pflanzen. Arkiv fur Botaiiik 

 IX. 12-28. 7 figs. 1910. 



