DISEASES OF PLANTS. 771 



tions under which the parasite Uves. Where a certain host plant is found al)undantly 

 and the climatic conditions are favorable to the growth of the fungus the i)arasite will 

 reach a greater perfection as to its vitality and also a greater degree of systematic 

 stability. On the other hand, if the sujjply of necessary host i)lant is limited and 

 the fungus is near the limits of its natural habitat, its development becomes weaker 

 and this weakness is expressed by less sharply defined differences and by a marked 

 reduction in the a1)ility of the fungus to attack new species of host jjlants. — f. w. 



WOLL. 



The specialization of black rust of cereals in Sweden and other countries, 



J. Eriksson {CenthJ. Bait. n. Par., 2. Aht., 9 [1902), Nas. 16, pp. 590-607; 11-18, pp. 

 654-658). — A review is given of the previous investigations of the author on the 

 specialization of cereal rusts, and the results of inoculation experiments with Pucci- 

 nia graminh from the barberry upon 52 species of grass are described. Upon all of 

 these species of grass the author was successful in securing infections. He is led to 

 conclude that the phenomenon of rust specialization can no longer be attributed to 

 internal, innate tendencies on the part of the rusts to produce new forms, l)ut that 

 it is due to the characteristics of the host plants and the influence of climate, etc., 

 acting upon the parasite. 



Cereal rusts, D. McAlpine {Jour. Dcpt. Ayr. Victoria, 1 [1903), No. 4, pp. 425- 

 4^1)- — A general discussion is given of the nature of rusts and thelos.ses due to them; 

 and the results obtained in the experimental plats, in which varying susceptil)ility 

 of varieties is shown, are given. The most injurious species of rust in Australia is 

 that known as the summer rust {Puccinia yramini.^) . Brief notes are also given on 

 the barley and oat rusts {P. ninijtJrx and P. graminis) . 



Wheat and barleyrusts, D. McAlpine {.Tour. Dept. Agr. Victoria, 1 {1902), No. 5, 

 /I. 529, pi. 1). — Illustrated not^s are given of Puccinia, graminl.'< occnrring cm barley 

 and wheat, P. Iriticina on wheat, and P. simplex on barley. 



Culture experiments with rust fung-i, H. Klebahn {Ztschr. Pflanzenkrank., 12 

 {1902), Nos. 1-2, pp. 17-44; 3, pp. 1S2-151, figs. 5) .—The result of extended culture 

 experiments with a number of rust fungi is reported. Among those studied were spe- 

 cies of Melampsora of willows and poplars which have their ca^oma stage on Allium, 

 those occurring on willows and Galanthus, on willows and Ribes, and studies of 

 Melampsora larici ilaphnoidcs, M. pinitorqua, M. larici tremuLr, M. rostrupii, and M. larlci 

 populina; also experiments with the leaf rusts of pine, the bark rusts of pine, various 

 species of .Ecidium and of Puccinia, together with species of GymnosjMjrangium. 



A classification of the rusts of the Umbelliferae, C. B. Flowkight ( Gard. 

 Chron., 3. ser., 32 {1902), No. 825, p. 282). — A brief account is given of the recent work 

 of Lindroth on the classification of the Uredine?e known to occur on various species of 

 Umbellifera?. In this monograph descriptions are given of all the known species, 

 which amount to nearly 90. The author has grouped the English species into 4 

 groups, l)ased upon the proposed system of classification. 



Rust of Andropog-on sorghum, W. Busse {Per. Deut. Bat. Gesell., 20 {1902), No. 

 a, ]>p. 281-291, j>l. 1; ((l>.^. ill .Tour. Roij. 3ficros. Soc. [Loyidon], 1902, No. 5, p. 592). — 

 The author has studied the occurrence of this fungus in German East Africa, where 

 it sometimes causes heavy losses in the crop of millet. He has arrived at the con- 

 rhision that the fungus is that described by Cooke as Piiccinia jnirpurea. The tech- 

 nical characters are briefly described, and the writer states that this is the same rust 

 as that known as sorghum rust in India, which has been attributed to P. penniseti. 



Rust of timothy, J. Eriksson {Ofvers K. Srenska Vetensk. Akad. Forhandl., 59 

 {1902), PI). 189-198; ahs. in Jour. Roy. Micros. Soc. [London], 1902, No. 5, pp. 592, 

 593). — According to the author, the rust found on timothy is a separate and distinct 

 species, and has been named Puccinia phlei-prati'nsis. Infection experiments have 

 been tried by the author to trace the life history of the fungus, and after considerable 

 ditiiculty the spermagonia and a^cidia were produced. The author is of the opinion 



