52 EXPERIMENT STATION RECORD. 



of Pnccinia graminis on barberry leaves and of Peronosporn parasitica in the 

 stems of s<inie erucifer were clearly differentiated. 



It is claimed that iu properly stained sections the mycelial threads are 

 colored a deep pink in strong contrast to the blue coloring of the tissues of 

 the host. 



The life history and cytology of Sorosphaera graminis, E. J. Schwartz 

 (Ann. Bot. [London'], 25 (1911), No. 99, pp. 791-797, pi. i).— This is a more 

 extended discussion of this pai'asite (E. S. R., 24, p. 742), in which its occur- 

 rence, the structure and appearance of the diseased roots, and the cytology 

 and affinities of the organism are given. 



8. graminis, associated with nematode galls, was found to be parasitic on 

 the roots of various grasses. The fungus itself causes no hypertrophy of 

 diseased roots. 



An outbreak of rusts, G. E. Stone (Massachusetts Sta. Bpt. 1910, pt. 1, p. 

 14^i). — ^Attention is called to rusts of various plants which have been more or 

 less troublesome during the season covered by the report. These include the 

 rust on the apple, hawthorn, ash, hollyhock, rose, and quince. The apple rust 

 is said to have been particularly common, and It is stated that the hawthorn 

 has been affected to such an extent that nurserymen have become deeply inter- 

 ested in its control in their nurseries. 



Note on the biology of the genus Septobasidium, T. Fetch (Aivn. Bot. 

 [London], 25 (1911), No. 99, p. 8.'i3). — ^This genus as instituted contains cer- 

 tain tropical and subtropical species of basidiomycetous fungi, included by 

 previous authors under Thelephora, Lachnocladium, Corticium, etc., which 

 encrust the stems, twigs, or leaves of various living plants with no noticeable 

 injury to the host. 



From an examination of a long series of specimens it has been determined 

 that these fungi are parasitic on colonies of scale insects which they overgrow 

 and destroy completely. They do not, however, live on the secretion of the 

 insects but upon the insects themselves, and, therefore, they are biologically 

 similar to the genus Hypocrella among the Pyrenomycetse. 



Timothy rust in the United States, E. C. Johnson ( U. 8. Drpt. Agr., Bur. 

 Plant Indus. Bui. 224, PP- 20). — This paper discusses the present known dis- 

 tribution and relationship of the timothy rust (Pnccinia iMei-pratensis), 

 summarizes previous investigations of this disease in Europe and America, and 

 gives new information on its physiological specialization, methods of winter 

 survival, and the resistance of various timothy varieties to the rust. 



The rust mycelium was found to live through the winter in plants grown 

 at the Arlington Experiment Farm. Inoculation experiments showed that the 

 rust can be easily transferred to various grasses, and by using bridging hosts 

 it can infect several cereals which it will not attack directly. 



The aecidial stage of this rust is not definitely known. In a study of the 

 resistance of varieties of timothy to the rust in 1908 and 1909, W. J. Morse 

 found that the resistance " ranged from to 98 per cent."' Greenhouse tests 

 with resistant varieties showed a wide difference in the percentage of inocu- 

 lated leaves which did not become infected when compared with the figures on 

 rust resistance in the field, but when the severity of the infection and not the 

 percentage of infected leaves was considered, the relative resistance of the 

 various strains as obtained in the field was fairly well maintained in the 

 greenhouse. 



Breeding varieties resistant to this rust is suggested as a method of com- 

 bating it. 



American maize smut, T. H. Johnston (Agr. Gas. N. 8. Wales, 22 (1911), 

 No. .'/, lip. 319, 320, pi. 1). — Attention is called to the introductiou into New 



