lOiO] AGRICULTURAL BOTANY. 327 



Ihorefttre, of tlie offocts of lli(> cold wcatlici' (»u various plaiits f^'rowiiij; in the 

 open air in difforent localitit's, \\iiic-h aro nanu'tl witli an extensive list of plants 

 concerned. 



The eftect of aeration on the roots of Zoa mays, I, C (). Heals {Proc. Jiid. 

 Acad. ScL, 1011, pp. 177-lSO, figs. 3). — Tliis experiment, as brietly described, is 

 considered to show the great importance of the presence of air in contact with 

 tlie roots not only for the normal cT'^wth of plant tissue but also for obtaining; 

 the maxiniiuu iilant jii'owtli. 



The action of one crop on another, S. Pickeuing {Jour. Roy. Ilort. Sac, ^J 

 (lyiO), Xu. 2-3, pp. 372-^iSO, pis. 5, fig. l).—lt is held that the toxicity of heated 

 soils is line to the decomposition of the orjianic matter in tlie soil, and it is 

 thought that a like decomposition must occur, tliough less readily, at ordinary 

 atmospheric temperatures. As most of the organic matter in soil is a product 

 of plant growth, it follows that more toxin will be produced by plants grow- 

 ing than Avhere they are not, hence the toxic effect of one plant or another. 

 The ultimate decomposition of the toxin into food material demonstrated by 

 the results with heated soils also explains the. increased fertility in a soil 

 which has grown a surface crop as soon as that surface crop is removed and 

 the production of toxin ceases. 



What the toxic substance is has not yet been ascertained, but an examina- 

 tion is now in progress from the chemical point of view. Some of tliese ex- 

 periments, as here noted, indicate that the toxin is either a substance which 

 can be oxidized or a reducing body. It has been found that such a body is 

 present to a certain extent in extracts from all soils, and that it is increased 

 by growing a crop in the soil or still more by subjecting it to heat. The 

 question is evidently one of great complexity. 



The effect of centrifugal force on plants, F. ]\I. Andrews {Proc. Iiid. Acad. 

 /S'ei., 1017, p. 175). — (Kdugonium ciUatum was centrifuged, 1,500 gravities being 

 employed. Apparently the protoplasm was not detrimentally affected. 



Barium in plants and soils (Kentucky Sta. Rpt. 1918, pt. 1, p. ^2). — A brief 

 summary is given of the results of an investigation by J. S. McHargue, a full 

 account of which has already been noted (P]. S. II., 40, p. 819). 



Abnormal abundance of calcium oxalate in plants, N. Patschovsky (Biol. 

 ZcntbL, 3D (1910), No. 11, pp. ^81-480). — An account is given of studies regard- 

 ing the presence in soluble form in plants of oxalates. 



On the localization of anthocyanin in the spring" leaves of some trees 

 and shrubs in the temperate regions of Japan, T. Ichimura (Bot. Mag. 

 [Tohgo], 33 (1919), No. 385, pp. i2-/5).— Tabulated results are given of obser- 

 vations regarding the presence of anthocyanin and its histological distribution. 



In a majority of G9 species, anthocyanin is localized in the palisade layer. 

 It is conlined to the epidermis or leaf hairs in a few. It is noted tl;at the 

 lower epidermis and the lower hypodermal layer are richer in pigment than 

 the upper ones in case of young leaves. The distribution of transitory antho- 

 cyanin in young leaves is also Indicated. 



A new chromogen, producing a blue pigment in Galanthus nivalis, T. 

 Tammes (Rcc. Trar. Bot. Nccrland., 15 (1918), No. 1, pp. 1-16). — A chromogen is 

 reptjrted as producing an ultramarine blue coloring material under cimditions 

 of fi-ee oxygen access and temperature of 20 to 100° O. (08 to 212° F.) in 

 all parts except bulb and roots of O. nivalis and other species of Galanthus. 



The opening of anthers in Solanacene, I. Namikawa (Bot. Mag. [Toktfo], 

 SS (1919), No. 387, pp. 62-69, figs. 7). — This is :in account of studies on the open- 

 ing of anthers in Lycopersicum csculcntuni, ^'^<^hiza)lt}lus piniialus. Capsicum an- 

 nuuw, Holaiium nigrum, »*?. dulcamara, »s'. tuberosum, S. melongenn, Petunia 

 violacea, Nicotiana alata grandiflora, and Physalis alkelcengii. 



