1918.] AGRICULTUEAL BOTANY. 731 



degree the harmful effects of infrequent changing. Magnesium injury was 

 more marked in case of frequent changing. 



Some experiences in the use of copper sulphate in the destruction of algae, 

 G. Embrey (Analyst, ^2 (1911), No. J,97, pp. 264-271, pi. i).— This is a report, 

 with discussion, of a number of experiments following up the studies of Moore 

 and Kellerman (E. S. R., 17, p. 12) on the effects of combined copper on algae 

 in reservoirs. 



Chara was destroyed by a solution of 1 part copper sulphate to 3,000,000 

 parts water. This plant (as well as its parasites) appeared, however, on 

 careful study, to be free from the odor ascribed to it Further tests seemed 

 to identify this odor as due to Tabellaria or Asterionella, or both, and to deter- 

 mine its character as that of a fatty oil colored with diatomiu, a body closely 

 allied to chlorophyll. The changes supposed to occur in the copper compound 

 are briefly indicated. It is thought that oxid of copper is the real poisoning 

 agent, and if, as is supposed, the fatty oil serves as a lubricant, the oxidation 

 of the copper compound may be the real cause of the death of the plants. 



The copper sulphate should probably be added not later than the end of 

 April. This destroys the desmids and diatoms and prevents the formation of 

 an organic mass into which the rootlike thallus of Chara can penetrate. This 

 organism is almost eradicated from water subjected to this treatment. 



Serodiag'nostic studies on gymnosperms, R. Koketsu (Bot. Mag. [Tokyo], 

 SI {1917), No. 365, pp. i4^-J55).— This is an attempt to extend the method of 

 serodiagnostlc study to gymnosperms, a number of these having been em- 

 ployed in this investigation, the methods and results of which are detailed. 

 It is claimed that the indicated relationships of the plants employed agree 

 in a general way with those already expressed in modern classification. 



Studies on root nodules, K. Shibata and M. Tahaea {Bot. Mag. [Tokyo], 

 SI {1917), No. 366, pp. 157-182, pi. 1, figs. 16).— The authors report studies on 

 the comparative anatomy of root nodules, classifying the plants examined so 

 that the first type of root nodules is represented in Coriaria, the second In 

 Myrica, the third in Gale (Myrica gale), and the fourth in Alnus, Elaeagnus, 

 and Ceanofhus. 



Variegation in Plantago, S. Ikeno {Genetics^ 2 {1917), No. 4, pp. 390-416, 

 figs. 2). — In a study of a variegated garden race of Plantago major asiatica 

 the author found this plant to breed true to type generally by self-fertilization, 

 though this process sometimes gave a few self-colored green plants. The Fi 

 hybrids between variegated and ordinary self-colored green plants are self- 

 colored gi-een irrespective of the direction in which the cross is made. The 

 self-colored green plant contains two factors, showing variegation only when 

 both are absent. Each of these factors is able, independently of the other, to 

 produce the exact intensity of green produced by both together. The Fj plants 

 which breed true to greenness in successive generations (constant green plants) 

 are not always of the same genetical constitution, as has been shown by hybridi- 

 zation tests. Each of the few green plants produced by self-fertilization of 

 variegated plants exhibited segregation In approximately the ratio of three 

 green to one variegated. 



Further tests are in progress regarding the genetical behavior and constitu- 

 tion of these plants. 



Recent studies on variation in some species of micromycetes, Elisa Mutto 

 and G. Pollacci {Atti R. Accad. Lincei, Rend. CI. Sci. Fis., Mat. e Nat., 5. ser., 

 26 {1917), I, No. 9, pp. 498-502), — The investigations previously reported (E. S. 

 R., 35, p. 547) have been\followed by studies with cultures of Coniothyrium tiro- 

 lense and Phyllosticta pirina on different media, the results of which are tabu- 

 lated and contrasted. 



