10 TIMOTHY EUST IN THE UNITED STATES. 



experiments it may be concluded that the rust in the United States 

 and the rust in Europe are identical, and the statement by Eriksson ^ 

 that it" is not a well-fixed species is substantiated. Although timothy 

 rust can easily be transferred to Avena sativa, Eriksson ^ and Carle- 

 ton ^ have sho^^^l that the uredo of Puccinia graminis avenue Erikss. 

 and Henn. can not be made to grow on timothy. This rust, however, 

 can easily be transferred to Dadylis glornerata and Arrlienatlierum 

 elatius.' Timothy rust also transfers to these hosts (Table I). These 

 rusts, therefore, although not identical, have many characteristics in 

 common, wliich indicates that there probably is a very close relation- 

 ship between the two. 



A small number of experiments to test whether or not the timothy 

 rust can be transferred by means of bridging hosts to various cereals 

 which are not successfully mfected directly from tmiothy were tried 

 and it was foimd that by using Avena sativa as a bridgmg host the 

 rust easily transferred to Hordeum vulgare (4 times in 10 trials) ; by 

 usmg Festuca elatior it transferred to Hordeum vulgare (twice in 10 

 trials) and to Triiicum vulgare (once m 10 trials); and by using 

 Dactylis glomerata it transferred to Triticuw, vulgare (once m 5 trials). 

 By the use of the bridging hosts the rust undoubtedly could be made 

 to transfer to many grasses on which it wUl not grow when coming 

 directly from timothy, but on which it might continue to grow after 

 such a transfer. That this to some extent takes place ui nature is 

 very probable, and these trials, together with recent experiments of a 

 similar nature on the rusts of grams,^ tlirow much light on the pos- 

 sible origin of many of the so-called "physiological species" of rust. 



iECIDIAL STAGE AND NOMENCLATURE OF TIMOTHY RUST. 



The gecidial stage of the rust is not definitely known. Eriksson 

 and Hemiing * noticed that the timothy in the neighborhood of bar- 

 berries was not affected, while other grasses in the same locality were 

 rusted. In two trials in 1891 they were unable to secure infection 

 on timothy with £ecidiospores from Berberis vulgaris. In 1892-3 

 secidia on Berhens vulgaris were obtained l)y them after inoculation 

 with teleutospores of timothy rust once in nine trials, and that in only 

 one place of inoculation against 92 places inoculated vnth negative 

 results. This one positive result may have been due to accidental 

 infection from some other source, as two leaves on the same bush 



' Loc. cii. 



« Carleton, Mark Alfred. Cereal Rusts of the United States. BuUetin 16, Division of Vegetable Physiol- 

 ORy and Pathology, U. S. Dept. of Agriculture, 1899, pp. (il-(V2. 



3 Freeman, E. M., and Johnson, Edward C. The Rusts of Grain in the United States. Bulletin 210, 

 Bureau of Plant Industry, U. S. Dcpt. of Agriculture, 1911, p. 10. 



« Eriksson, Jakob, and llenning, Ernst. Die Haupt-Resultatc einer neuen Untersuchung uber die 

 Getreideroste. Zeitschritt fiir Pflanzenkrankheitcn, vol. 4, 1894, p. 140. 

 22A 



