AGRKMI.I i l: \l. BOTANY. 957 



root tubercles of Robinia pseudacacia, Tetragonolobus siliquosus, and several species of 

 Cytisus, Orobus, and Vicia, and he claims in every case to bave determined the 

 possibility of gas exchange through the cortex of the roots. 



The effect of self-fertilization in the Leguminosae, < >. Kirchneb {Naturw. 

 Ztschr. Land u. Forstw., 3 [1905), Nos. /, pp. 1-16; ?, pp. }:» 64; ./, pp. 97-111).— 

 Observations are given on the self-fertilization ofaboul LOO species, of Legumii 

 representing 34 genera, the data in many instances being compiled from various 

 sources, and in a number of cases the statements were confirmed by the author. 

 A-boul one-third of the species arc reported as being self-sterile. 



The effect of light on Melilotus alba, R. \V. Coppedge Trans. Kans. Ar.nl. 

 Sci., .'" I 1905 I, /-/. /, pp. 97- 105 i .- The author describes a iiiiimI.it of experiments t" 

 tesl the effect of lighl on sweel clover, studying its effect on tin- nutation <>f Leaves 

 and -t t 1 1 1-. the relation between movement and strength of light, tin- relation between 

 light and carbon dioxid L r as in forming starch, and the time at which starch was 

 formed and disappeared in the plant. 



[n studying the nutation of the leaves and stem-, the author found that the hot- 

 Bun position assumed by the plant depends on theamountof moisture in the soil 



and not on the condition of the atmosphere, and that the opening and closing of the 

 Btomata depend on the relative humidity of the atmosphere. Nutation he found to 

 take place in almost the entire stem of the young plant, being most noticeable in the 

 pulvinus and decreasing toward the roots. As the plant grows older the region of 

 nutation is diminished. 



Experiments to determine whether the movement of the plants and Leaves 

 depended on the light only showed that light alone was the cause of the normal day 

 movements of the plants, and the rate of movement was found to depend on the 

 Btrength of the light. 



In determining the relationship between light and carbon dioxid in starch forma- 

 tion the author experimented with haves in different temperatures, in different 

 colored lights, etc., and found that only in the presence of both Light and air was 

 starch formed and that it disappeared from the leaf when air only was present. 



The experiments as to the time when the starch left the plant indicated that there 

 was a gradual decrease of starch after midnight, with its reappearance in the morn- 

 ing. In one series of experiments all the starch had disappeared at 5 o'clock in the 

 morning. ■ In another series leaves were examined every half hour, beginning at 

 4 o'clock in the morning, ami at this time the cells were crowded with starch. At 

 4.30 most of the starch had gone from the palisade cells; at 5 o'clock it was present 

 only in the sieve-tnhes, and a little in the cells bordering them; and at ">.;;(> all the 

 starch had gone from the leaf. At fi o'clock starch began to appear again in the 

 palisade cells, showing that it disappears first from these cells and also reappears 

 first in the palisade tissues. 



The action of sulphur dioxid on plants, A. Wieler i Untermchungen iiber </<>■ 

 Einvrirkung Bchwefliget Saure auf dit Pflanzen Berlin: Borntraeger Bro., 1905, />]>. 

 VII 427; rev. m Natun [London], IS | 1906), No. 1895, pp. S85, 886).- A monograph 

 dealing with the injurious action of sulphur dioxid «,n plants, especially on forest 



trees. 



About one-half ot the volume is taken up with accounts of experimental examina- 

 tion ot the action «,[ the gas on plants, after which the demonstration ol its action on 



leaves and proof that it enters through the Btomata are given, together With accounts 

 of its action on the soil, relation between height of trees and constitution of soil, 

 resistance ot plants to the gas, and the amount ot gas m the air <»t contaminated 

 regions. 



It is claimed that sulphurdioxid was found in the leaves of all plants examined as far 

 as 8 kilometers from any known source ol pollution, but there was no relation between 

 the degree of injury and the concentration of the poison in the air, nor could any 



