1918.] AGRICULTURAL, BOTANY. 629 



in higher concentrations produced a slight but unmistakable stimulation of 

 growth in case of this plant, but it is suggested that this may have been due 

 to a resulting greater availability of the phosphorus or of other soil nutrients. 

 Pronounced and very specific toxic effects followed the use of boron, chromium, 

 iodin, lithium, and mercury, and it is thought that it may be possible to recog- 

 nize a poisonous ingredient in plants, as in animals, by its effect on the 

 organism. 



Certain features of the localization of injury in the plants suggest a relation 

 to transpiration, that is, the poison's being carried into the plant incidentally 

 by the transpiration stream and producing injury only when and where evapo- 

 ration sufliciently increases concentration in a local tissue area. Chromium 

 may prove to be an exception in this regard. 



Sterilization of popcorn, R. O. Beigham {Rpt. Mich. Acad. Sci., 17 {1915), 

 pp. 190-193) .—lieqmring several sterile seeds of popcorn for work in progress 

 on the availability of nitrogen from certain organic compounds in sterile and 

 in inoculated cultures for the growth of plants, the author carried out experi- 

 mentation from which he concludes that mercuric chlorid, even at very low 

 concentrations and for short durations of time, is toxic to popcorn seedlings, but 

 that sulphuric acid (sp. gr. 1.84) used to treat the seeds for four minutes is 

 the best disinfectant so far tested. While about 90 per cent of the seeds were 

 free from organisms, yet absolute sterility ctsuld not be obtained as some 

 fungi probably lie too deep in the seed coat to be reached by the disinfectant. 



The presence of ammonia and of ammonium salts in plants, T. Weevers 

 {Rec. Trav. Bot. N6erland., 13 {1916), No. 2, pp. 63-iO//).— Previous study of 

 potassium in plants (E. S. R., 26, p. 823) having led to a similar study of the 

 localization of ammonium, the author gives in considerable detail the results 

 obtained with different plants by the employment of a method, the limitations 

 of which are indicated. 



In the phanerogams investigated, free ammonia was found only in the root 

 nodules. Among the cryptogams, it was found in some of the Hymenomycetes 

 (Clitocybe infundibuliformis) and lichens {Peltigera canlna). Ammonium salts 

 were found in all species with the exception of certain forms growing in marshy 

 soils. At a given time of the year, like portions of plants of the same species 

 gave sensibly the same percentages, the influence of habitat appearing to be 

 slight. 



A method for approximating sunshine intensity from ocular observations 

 of cloudiness, F. M. Hildebrandt {Johns Hopkins Univ. Circ, n. ser.. No. 3 

 {1917), pp. 205-208). — ^This method, as briefly des*-ribed, is based upon the 

 assumption that, while solar radiation alTects plants in other ways than tlirough 

 its heating effect, by far the greater part of the sunshine energy absorbed by 

 plants is converted into heat (largely as latent heat of the vaporization of 

 water). It seems probable that the total of the other effects produced upon the 

 plant may be more or less proportional to the total energy equivalent of sun- 

 shine. The method of measurement of light here described, although only a 

 rough approximation depending upon the heating effect of the sunshine, is said 

 to have given numbers rather definitely correlated with plant growth. 



Inventory of seeds and plants imported by the Office of Foreign Seed and 

 Plant Introduction during the period from October 1 to December 31, 1914 

 {U. S. Dept. Agr., Bur. Plant Indus. Inventory No. Jfl {1917), pp. 67, pis. 4).— 

 This is an inventory of seeds and plants imported, mostly from Asia, during the 

 period from October 1 to December 31, 1914, about 370 numbers being reported 

 upon. 



