132 EXPERIMENT STATION RECOED. tVo!. 36 



transfer of magnesium in considerable quantity to the grains, where it is 



tixed. 



The root nodules of Ceanothus americanus, W. B. Bottomley (Ann. Bot. 

 [London], 29 (1915), No. 116, pp. 605-610, pi. i).— Giving an account of inves- 

 tigations on C. americanus, the author states that the root nodules of this 

 plant are modified lateral roots, perennial in character and increasing each 

 year by the formation of endogenous outgrowths or branches structurally 

 similar to the branch from which they primarily arise. Each primary nodule 

 or branch develops four zones designated respectively as meristematic ( apical ) , 

 infection, bacterial, and basal. The younger bacterial cells contain rod-shaped 

 organisms, the older ones spherical bodies, the latter being the bacteroid condi- 

 tion of the active nitrogen-fixing rod-shaped bacillus. The bacteria, when iso- 

 lated and grown in pure culture, are able to fix atmospheric nitrogen and are 

 considered to belong to the Bacillus radicicola group. 



The aerating system of Vicia faba, C. Hunteb (Ann. Bot. [London], 29 

 (1915), No. 116, pp. 627-63^, figs. 6). — A description is given of the aerating 

 system demonstrated for V. faba. It is thought that the division of the air 

 cavities in young internodes facilitates gas interchange in the active region 

 of the growing point. It is suggested that the production of lysigenic cortical 

 air cavities in old internodes is a device to assist in respiration by the cortical 

 cells of the old root. The development of the intercellular space system of the 

 root tip is thought to show the great importance of the aerating system in the 

 most active regions of cell development. 



On the coagulation of Hevea latex and a new method of coagulation, B. J. 

 Eaton and J. Grantham (Agr. Bui. Fed. Malay States, If (1915), No. 2, pp. 26- 

 30). — Reporting work designed to test the hypothesis of Whitby (E. S. R., 29, 

 p. 149) that the spontaneous coagulation of Hevea latex is brought about by 

 a coagulating enzym, the author claims that these experiments indicate that 

 this natural coagulation of the latex of H. brasiliensis is due to certain bac- 

 teria which infect the latex after collection. There are two types of organism, 

 one (favored by aerobic conditions) which tends to inhibit coagulation and 

 produces an alkaline slime in the presence of air, and the other (favored by 

 anaerobic conditions) which effects coagulation of the latex. The coagulation 

 of the latex under anaerobic conditions is not constant, owing, it is thought, 

 to a variation in the constitution of the latex. By the addition of various 

 sugars, coagulation under both aerobic and anaerobic conditions always occurs. 

 This is thought to be explainable on the supposition that a medium is formed 

 more favorable for the organisms which produce coagulation and less favorable 

 to those producing putrefactive changes. 



The assimilative capability of witches' brooms on cherry, E. Heineicheb 

 (Ber. Dent. Bot. Gesell., 33 (1915), No. 5, pp. 21,5-253, figs. 2).— It is stated that. 

 In experiments described, considerable assimilation of carbon dioxid was accom- 

 l.lished by the foliage of witches' brooms in case of cherry. 



Dwarfing effect of trees upon neighboring plants, J. Y. Bergen (BoL Gaz., 

 60 (1915), No. 6, pp. 491, /,92).— Discussing the factors generally mentioned in 

 connection with the deficient growth of plants in the shade of trees, namely, 

 shading, abstraction of water and of salts, and the possible excretion of inju- 

 rious substances by the trees, the author records observations made during 

 the very ral.iy summer of 1915, in Cambridge, Mass., on some growing plants 

 shaded by a belt of deciduous trees. 



It Is stated, regarding Aster novw-angliw, Asclepias tuberosa, and Helianthus 

 grosse-serrntus, that, while none of these flourished as well as did other indi- 

 viduals growing in oi>en ground, all were perhaps twice as tall as during an 



