DISEASES OF PLANTS. 1139 



oU ;nid P. thalictri) are borne on sep.-irjite mycelial threads. During the inves- 

 tigations the author cultivated pure growths of the Lima bean mildew and 

 found that in mixed cultures oospores were always produced. Cultures are 

 now being carried on to obtain mycelia from single spores, and if the theory 

 of sexual mycelia is correct, these should produce no oositores. 



Studies of the potato fungus (Phytophthora infestans), L. II. Jones and 

 X. J. (JiDiJiNos (.l/jv. in Scinicr, ii. scr.. 2!) iHKl!)). Xo. 737. p. 271). — The 

 authors state that pure cultures of the potato-rot fungus have I)eon maintained 

 fur 4 years in the laboratories of the station. Sealed gelatin cultures have been 

 maintained for 7 months, remaining alive but slow in starting growth. 



Some noteworthy morphological characters have been observed, among them 

 haustoria-like branches in potato tissue, the abundance of cell partitions in old 

 cultures, an apparent differentiation into two sti'ains, one exceeding the other in 

 vegetative vigor, and oogonia-like bodies produced sparingly on certain media 

 and frequently on others. 



It was found that infection normally occurs through the eyes of the tubers 

 before digging and in storage, but occasionally through wounds or lenticels. 

 Wide differences were found between different varieties as to the ease of leaf 

 infection and subsequent rate of spread, which leads to the conclusion that the 

 disease resistance of the leaves may reside in the mesophyll as well as in the 

 epidermal tissues. 



Similar differences occur in the rate of development upon sterile blocks cut 

 from the interior of the potato tubers, and these differences are not due to the 

 acid reaction of the cell sap. 



A disease of tomatoes, V. Vera (Prog. Agr. ij Pcciiario. l'> {190!)), \o. 613, 

 pp. 64-66, fig. 1). — -An account is given of a disease of tomatoes due to the 

 fungus Scptoria Igcopersici. The effect of the disease on the different parts of 

 the plant is noted with suggestions for its control. It is stated that the form 

 I)resent in Europe differs from that originally described as coming from Argen- 

 tina and that the former is probably .S. Ujcopersici otropccc. 



Studies of two species of Gloeosporium, E. Lasnier (RuL Trimcst. Soc. 

 Mi/ci/l. France. 2) (190S). Xo. 1. pp. 17-'i3. pis. 3). — Studies were made of G. 

 (■(tttlci/o' found on the leaves of certain species of Cattleya, and of (1. )nus(irum 

 on banana fruits. 



The morphological and biological characters of each fungus are described, 

 and the author concludes that they are both saprophytes. The perfect form of 

 neither species has been recognized. The characteristics, as shown in culture 

 media, are described at length. The species occurring on orchids somewhat 

 resembles that descrilied by Cooke and Massee under the name (1. ranillfr. That 

 occurring <m the banana is strictly saproi)hytic, attacking the fruits only after 

 they have attained complete maturity. 



Investigations on the development of Gloeosporium nervisequum. A. (Juil- 

 LiERMONU (R< r. (Irn. Hot.. 20 (IDOS), Xos. 23S. pp. 38.')-.',00, />/.<. 3, figs. .'> ; 239, pp. 

 'i29-J,.',0. figs. .7; 2.'i0, pp. -',.'i9-.'i60, pl.<t. 6). — A detailed study is given of the syca- 

 more anthracuose. CI. ncrrisrc/tnini or (Inomonia rcnrta, as its i)erfect form is 

 known. The fungus was <arefnlly isolated and cultivate<l in a number of 

 media, but in none of them was the author a!)le to recognize the yeast forms 

 .lescribed by Viala and Pacottet (E, S. It., 18, p. .347). The author thinks that 

 probably these authors had impure cultures and that the yeast and cyst forms 

 were due to the development of some other organism. In other resjiects the 

 general featin-es of develoimient agree. 



Experiences on the control of grape downy mildew in 1908, (i. Chappaz 

 (/'/•Of/. .\gr. rt Vit. (Ed. VExi-Ccntrr) , 30 (1909), No. 10, pp. 285-289) .—The 

 results of sjjraying exiterinients with (liff<>rent fungicides for the control of 



