230 EXPERIMENT STATION RECORD. 



iujurioiis effect of smoke aud factory fumes on soil aud vegetation in the 

 region of Aix-la-CLaipelle. 



It was found that" the factory fumes contained sulphuric, sulphurous, and 

 hydrochloric acids, which dissolved the lime of the soil and thus rendered the 

 soil increasingly acid and interfered with the bacterial activity of the soil, 

 particularly nitrification. Liming corrected this condition and prevented de- 

 struction of plant gi-owth in case of forest trees. The chestnut appeared to be 

 one of the most resistant trees to acid fumes. In addition to the harmful effect 

 on the soil, the fumes occasionally caused direct injury by corrosion and by 

 deposit of soot ou the leaves. 



Premature fall of flower petals, H. Fitting (Jahrh. Wiss. Bot. [Pringsheim], 

 49 {191d), I<o. 2, PI). 187-263, figs. S; abs. in Ztschr. Bot., 4 {1912), No. 2, pp. 

 131-W3). — This is a detailed account of the author's study of the casting of 

 fresh and even of very young petals of Geranium pyrenaicum and several other 

 plants found to be highly sensitive to certain influences unfavorable in this 

 respect. Among these influences are gases and vapors in the atmosphere, par- 

 ticularly illuminating gas, carbon dioxid, tobacco smoke, chloroform, ether, 

 and hydrochloric acid ; high temperature, agitation, and dryness ; and wounding 

 of the ])etals. 



Some very sensitive plants showed reaction to the unfavorable stimuli within 

 a few seconds. The fall of the petals occurred after periods varying from a 

 few minutes to several hours. Further studies are contemplated. A bibliog- 

 raphy is appended. 



Bud mutations of Solanum maglia, E. Heckel {Compt. Rend. Acad. Sci. 

 [Paris], 153 {1911), No. 7, pp. 417-420). — In continuation of a previous note 

 (E. S. R., 20, p. 733), an account is given of a bud mutation of S. maglia pro- 

 duced by heavy manuring in conjunction with the use of artificial fertilizers. 



In 1910 the author obtained 5.5 kg. of tubers of the mutating form, most of 

 which were of a reddish violet color. These tubers were planted in April, 

 1911, and produced a considerable crop, many of the individual tubers weigh- 

 ing from 350 to 380 gm. and some of the hills yielding as much as 2 kg. The 

 plants appeared completely free from fungus diseases. 



Attention is called to some of the variations which have apparently become 

 fixed in this form, and the author notes the occurrence of violet colored tubers 

 both in this si^ecies and in S. commersonii. This is thought to indicate that 

 the contention that the Giant Blue, a well-known variety of S. tuberosum. Is 

 the same as the mutant of Labergerie is not correct. 



A study of hybrids between ZSTicotiana bigelovii and W. quadrivalvis, E. M. 

 East {Bot. Gaz.. 53 {1912), No. 3, jif). 243-24S, figs. 4).— Studies of these species 

 of Nicotiana have been carried through several generations, and the author has 

 discovei'ed 2 elementary species of N. bigelovii. In one the capsules are 2-celled 

 and selection of individuals has not increased the numbei', while in the other 

 species there is a tendency to more than 2 cells in the capsule, which tendency 

 is always transmitted. 



The author believes that the species N. quadrivalvis and normal N. bigelovii 

 are alike in all specific characters except the number of cells, and since they 

 give fertile hybrids it is proposed that the first species should be considered a 

 variety, its name being .A", bigelovii quadrivalvis. 



A retrogressive metamorphosis artificially produced, S. Alexander {Rpt. 

 Mich. Acad. Sci., 13 {1911), p. 198). — The author states that occasionally ma- 

 tured flowering buds of the peach inserted in a stock by bud grafting will 

 develop, in which case the peduncle increases to a length of 5 or 6 in., the sepals 

 grow to the size aud length of full-sized leaves, and the petals and stamens are 



