DISEASES OF PLANTS. 453 



figs. 20). — This is a more extended treatment of these fungi than the author's 

 previous papers on this subject (E. S. R., 24, p. 742), and includes studies on 

 the polymorphism of the various species, the systematic value of the biological 

 conditions, and the taxonomic classification of the genera and species. 



The author describes as new 2 genera, Pleocouturea and Fumagospora, 4 

 subgenera, viz, Pleomorfen, Teichosporina, IMorfea, and Leptocapuodium, and 

 6 new species as follows: Plcosphcvria iJicis on the leaves of Qucrcus ilex, 

 Teichospora capnodioides on the dead bark of Populis alba, T. salicis on the 

 branches of Sallx cinerea, Limacinia spnngiosa on the branches of Nerium 

 vleandcr, Pleocouturea castagnei on the branches and foliage of Pyrus mains and 

 Eriohotrya japonica, and Fumagospora capnodioides on the leaves and foliage of 

 various plants. 



South African cereal rusts, with, observations on the problem of breeding' 

 rust-resistant wheats, I. B. P. Evans (Jour. Agr. ScL, 4 (.1911), No. 1, pp. 

 95-10.'/, dgm. 1). — Observations extending over 4 years but confined chiefly to 

 the wheat-growing districts of the Transvaal, inoculation experiments with 

 Puccinia graminis, and experiments on breeding rust-resistant wheats, are re- 

 ported. 



The following grain rusts were listed for South Africa : P. graminis on wheat, 

 barley, oats, rye, Dactylis glomerata, LoUum temulentum, and Festuca elatior; 

 P. triticina on wheat; P. coronifera on oats; and P. dispersa on rye. 



The black rust (P. graminis) is the most serious, usually being present on 

 all summer cereals, and in the low country the uredospore stage is often found 

 throughout the entire year. It is stated that this rust thrives best and does 

 the most damage during hot and dry spells, when it becomes so abundant that 

 the soil beneath the plants is colored a rusty brown with uredospores. The 

 rust first appears on wheat, and then on barley, oats, and rye in succession. No 

 fecidial stage of this rust was found in South Africa, and all attempts to ger- 

 minate the teleutospores have failed. The author distinguishes 3 forms of P. 

 graminis on cereals in South Africa, as follows: (1) A form on rye which never 

 appears until late in the season after the plants are headed, and has only been 

 found on the stalk but never on the leaves; this rust infects barley but not 

 wheat or oats, and all attempts to infect the rye leaves with it have failed. 

 (2) A form on wheat which infects wheat and barley, but not rye or oats; in 

 the field during winter months the barley remains free from this rust, while 

 adjacent wheat is badly rusted, but later during the summer the barley 

 becomes highly susceptible. (3) The form on oats which does not infect wheat 

 or barley. In India rust is unknown on oats, but the author states that the 

 Indian oats gi'own in South Africa are highly susceptible to both P. graminis 

 and P. coronifera. 



In the rust-resistant breeding experiments in which Bobs Rust Proof and 

 White Egyptian were used as immune and Wol Koren and Holstrooi as sus- 

 ceptible varieties, it was found that rust (P. graminis) from the hybrid is not 

 only able to infect the immune parent but produces a severer infection on the 

 susceptible parent than the rust from the parent itself. In other words, the 

 pathogenic properties of the rust seem to have become distinctly increased after 

 its sojourn in the hybrid plant and it produces a far more severe infection than 

 rust from the susceptible parent.. These hybrid plants, therefore, may play a 

 \ery important part in the transmission of rust organisms from susceptible to 

 immune varieties. The rust in the hybrid also developed a profusion of teleuto- 

 spores. while on both parent wheats teleutospores were very sparingly produced, 

 if at all. 



The control of the loose smut of barley and wheat, O. Appel and E. Riehm 

 {Min. Bl. K. Preuss. Verwalt. Landw., Donmnen u. Forsten, 7 {1911), No. 5, pp. 



