446 EXPERIMENT STATION RECORD. [Vol. 43 



Studies of the organism have led to the determination that the foot-rot as 

 Icnown in Illinois is due to a species of Helminthosporium, and it is stated that 

 this cereal disease, while of the general type of foot-rot known in Europe, 

 Australia, and elsewhere, is caused by an organism not heretofore designated 

 as a cause of foot-rot in any of the publications on this disease in other coun- 

 tries. The author claims that the foot-rot of wheat in Illinois should be 

 recognized as a disease quite distinct from all others ot similar type that 

 have been previously described. From his experiments it appeared that the 

 fungus is soil-borne, and it is considered probable that it is also seed-borne. 

 Further studies on the morphological and histological features and the relation 

 of the fungus to other species common to cereals are to be published later. 



A disorder of cotton plants in China; Club leaf or cyrtosis, O. F. Cook 

 {Jour. Heredity, 11 {1920), No. 3, pp. 99-110, figs. iO).— This is an account of 

 an abnormality^ said to be peculiar to certain sections, constituting one of 

 the principal limiting factors as regards cotton production in the central 

 Yangtze Valley. Although no diseased spots or other localized injuries of the 

 sorts usually caused by fungi, bacteria, or insect parasites could be demon- 

 strated, the plants showed dwarfing, distortion, discoloration, anomalous 

 branching, and other forms of abnormality, with corresponding reduction of 

 crop yields. The disorder shows analogy and resemblance to the leaf curl 

 caused elsewhere by plant lice. 



The degree of the disorder appears to be related to variety and also to ex- 

 ternal conditions, though plants standing side by side may show very different de- 

 grees of the trouble. In severe cases all of the floral buds are aborted so that 

 no more fruit is produced. Late plantings suffer worse in this respect. Hot 

 weather favors early development of the trouble. Humidity and shade may 

 be measurably protective. In club leaf, many branches develop that normally 

 remain dormant. Shortening of internodes is another feature. The reduction 

 and distortion of the leaves is one of the most prominent symptoms. Dis- 

 coloration varies with varieties and conditions. An angular mottling of the 

 leaf is a regular feature. Detailed discussion is given of the possibilities as 

 regards control, including selection for resistance and reduction of insect 

 parasites. 



On forms of the hop (Humulus lupulus) resistant to mildew 

 (Sphferotheca humuli) , II, E. S. Salmon {Jour. Genetics, 8 {1919), No. 2, 

 pp. 83-91). — In the article previously noted (E. S. R., 39, p. 147) it was stated 

 that plants resistant or innnune to hop mildew {S. humuli) separate into two 

 groups, containing, respectively, individual seedlings of the wild hop {H. lupu- 

 lus) raised from seed obtained from Vittorio, Italy, and a female variety of a 

 type having yellow leaves and being known as the golden hop. The present 

 article describes further experimentation carried out during 1917 with these 

 and other plants. 



It is stated that individual seedlings of the wild hop grown in a greenhouse 

 may be immune as regards leaf and stem to the attacks of the mildew. This im- 

 munity has been shown by the same seedlings throughout the growing season for 

 two consecutive years. Such seedlings, however, when planted out in the hop 

 garden may show susceptibility late in the growing season as regards the leaf 

 and strobile. The immune plant in the greenhouse may also show strictly local 

 susceptibility without loss of general immunity. The yellow-leaved female 

 variety of H. lupulus is immune to S. humuli, while the yellow-leaved male 

 variety is susceptible to this fungus. 



Failure of lettuce to head, A. J. Olney and W. D. Valleau {Ahs. in 

 Science, n. ser., 52 {1920), No. 1332, p. il). — According to the authors, the 

 various physiological troubles associated with the failure of greenhouse lettuce 



