422 EXPERIMENT STATION RECORD. 



iu pliauerogamic plants lias beeu shown by a number of investigators, and tlie 

 autlior has sought to extend the list to parasitic and saprophytic plants. 



An investigation was made of about 40 species of parasites, facultative 

 parasites (called relative parasites by the author), and higher fungi, in which 

 the nitrogen was determined. The author found that there was a variable 

 accumulation of nitrates in tbe plants which was influenced somewhat by the 

 amount of nitrogen contained in the substratum upon which they were growing. 

 Among the parasites and fungi growing upon trees the proportion of accumu- 

 lated nitrogen was always less than in the case of the facultative parasites. 

 The greatest amount of nitrogen was found in the facultative parasites con- 

 taining no chlorophyll. 



The carbon assimilation in plants, H. Euler {Ztschr. Physiol. Chcm., 59 

 (1909), No. 1, pp. 122-12Jf; abs. in Jour. Chem. Sac. [London], 96 (1909), No. 

 559, II, p. 423). — ^As a result of a study of the carbon assimilation in plants, 

 the author concludes that oxalic acid can not be considered an intermediate 

 product in carbon assimilation, but is rather an oxidation product of sugar, due 

 to respiration. His experiments, it is claimed, support Ewart's criticism of 

 Usher and Priestley's conclusion that formaldehyde is formed from carbon 

 dioxid and a chlorophyll extract in the light (E. S. R., 18, p. 540). 



The influence of magnesia on garden plants, particularly on roses, L. 

 Chenault and G. Truffaut (Jour. 8oc. Nat. Hort. France, J/, scr., 10 (1909), 

 June, pp. 370-373). — A brief account is given of the results of the application 

 of sulphate of magnesia to roses, the experiments being taken up at the sug- 

 gestion of the second author. Ash analyses of many garden plants showed a 

 high magnesium content, and it was thought that the addition of some form of 

 that element to fertilizers for garden plants and especially for roses would be 

 advantageous. Subsequent experiments confirmed this opinion. It is claimed 

 that in most soils the addition of 60 to 100 gm. of sulphate of magnesia will 

 prove of great benefit to roses. 



Studies on the oxidizing' power of roots, O. Scheeiner and H. S. Reed (Bot. 

 Gaz., Ifi (1909), No. 5, pp. 355-388). — This paper gives the results of a series 

 of studies upon the oxidizing power of plant roots grown in aqueous extracts 

 of soils and in solutions of various compounds. The results, it is believed, 

 throw some light on the action of plants upon the soil and indicate how soil 

 conditions affect certain functions of plants. The report is based on a previous 

 publication of the Bureau of Soils of this Department (E. S. R., 20, p. 1016). 



The eifect of the color of leaves on their internal temperature, and observa- 

 tions on the periodicity of the appearance of young' colored leaves of trees 

 in the Tropics, A. M. Smith (Ann. Roy. Bot. Gard. Peradctiiya, Jf (1909), No. 5, 

 pp. 229-298, figs. '2). — The results of studies made at the Peradenlya gardens on 

 the effect of color in leaves on their internal temperature and observations on 

 the periodicity of the appearance of young colored leaves of evergreen trees 

 growing in the gardens are given. 



The author found, by the aid of specially designed thermo-electric apparatus, 

 that the internal temperature of any leaf could be obtained within 0.5° C. Iu 

 still air with a humidity of about 70 per cent of saturation leaves were found 

 to re.ach a temperature 15° above that of the surrounding air. In the shade 

 such leaves have an internal temperature varying from 1.5° below to 4° above 

 that of the surrounding air under different conditions. 



The thickness of the leaf was found not to affect the final temperature 

 reached in the sunlight, although it did influence the time taken to reach that 

 temperature. Thick leaves in some instances took 10 minutes to attain a 

 steady temperature after exposure, while thin leaves required only 3 minutes. 



