DISEASES OF PLANTS. 243 



describes the various plauts and animals tliat form galls and tlie effect pro- 

 duced by tbem on tbe host plant. Chapters are given on the anatomy, chem- 

 istry, etiology, and biology of galls, followed by a brief account of gall-like 

 formations in animals. 



Peculiar spore forms of Botrytis, S. R. Price {Xeiv Phytoh, 10 (1911), No. 

 7-S, pp. 253-259, figs. 8). — A description is given of some unusual spore forms 

 of Botrytis occurring in connection with sclerotia found on the stem of hemlock 

 (Conium maculatnm). The spores are considered resting spores and, as they 

 occur in nature, may be regarded as constituting a normal phase in the life 

 history of the fungus. 



The Uredinales, A. Trotter {Flora Ital. Crijpt., 1 {,1908), No. J,, pp. lU, 

 figs. 58; 1 {1910), No. 7, pp. l.',5-33S, figs. 19).— This is a monogiaphic study 

 of the genera Uromyces, Puccinia, and Gymnosporangium. 



The spread of mildew from wild to cultivated plants, E. Xoffray {Jour. 

 Agr. Prat., n. ser., 21 {1911), No. IS, pp. 562-56.'^; ahs. in Internat. Inst. Agr. 

 [Rome^, Bui. Bur. Agr. Intel, wnd Plant Diseases, 2 {1911), No. 5, pp. 1152, 

 1153). — ^An account is given of the mildew Erisyphe communis, which at times 

 proves injurious to plants of economic importance in gardens and fields, the 

 spread of the fungus being to a considerable extent from wild plants. The 

 author enumerates a large number of species of plants that are hosts for this 

 mildew and recommends their destruction wherever possible. Where the mil- 

 dew appears on clover, as it frequently does, it is recommended that the clover 

 be mowed for a distance of a yard or more about the diseased area and the 

 plants removed to prevent further spread. 



The experimental Broduction of chlorosis in maize, P. Maz^ {Compt. Rend. 

 Acad. Sci. [Paris], 153 {1911), No. 19, pp. 902-905) .—X series of experiments 

 is reported in which corn was grown in water cultures containing a complete 

 nutrient solution, and comparisons made with similar cultures in which single 

 elements, as manganese, iron, sulphur, chlorin, lime, etc., were omitted. 



In the check culture the plants grew io maturity. Those deprived of sulphur 

 and iron were less developed, and within 15 days after being placed in the solu- 

 tion their leaves had taken on an abnormal color and well-developed chlorosis 

 appeared. This was evident soonest in the plants which had been deprived of 

 sulphur, appearing somewhat later where iron was wanting. The parenchyma 

 of the chlorotic leaves was very thin and transparent, showing that chlorosis 

 was a result of abnormal nutrition. A microscopic examination of the tissues 

 showed that the cells rarely contained starch in connection with the chloro- 

 leucites. The introduction into the nutrient solution of the compound which 

 was wanting caused the restoration of the green color and the plants developed 

 vigorously. 



In one series of experiments, drops of a dilute solution of sulphate of ammo- 

 nia were placed on chlorotic leaves. Within 3 days the green color had returned 

 and it spread slightly to the adjacent cells. The portions of the leaf not covered 

 by the sulphate retained their yellow color to the death of the leaf. 



In conclusion the author states that chlorosis may be induced by a number of 

 causes, and that it is possible that an excess of lime contributes to its produc- 

 tion. In addition, an absence of sulphur or iron favors chlorosis. Depriving 

 plants of chlorin, magnesium, and silicon did not cause chlorosis. 



Some troublesome diseases of the potato tuber, A. S. IIorne (Rpt. Brit. 

 Assoc. Adv. Sci., 1910, p. 578). — Attention is called to some of the diseases of 

 the potato which are characterized by the appearance of blotches and streaks 

 in the tuber. No organisms have been definitely associated with this, although 

 the seed tubers are believed to be liable to propagate it. The internal disease 

 is said to be often associated with the attack of Phytophthora infestans from 



