632 EXPERIMENT STATION RECORD, 



Inspection of commercial fertilizers, .7. P. Street et ai,. (New Jersey Stas. 

 Rl)t. 1906, pp. J7-,l'i). — This contains a brief statement regarding the fertilizer 

 inspection during 1906 reported in detail in Bulletins 196 and 198 of the station 

 (E. S. R., IS, pp, 433, 821) and a compilation representing 3,462 analyses by the 

 New Jersey Stations of 174 different materials of value for fertilizing purposes. 



AGRICULTURAL BOTANY. 



Nature and development of plants, C. C. Curtis (Neiv York, 1907, pp. VII 

 +^7/, figs. 3.'i2). — This work is not intended as a text-boolv and does not follow 

 the usual lines of such books, but is designed by the author to give the reader 

 a point of view from which to consider the plant world. The first part is a 

 study of the fitness and adaptation of the leaf, root, and stem of the plant to 

 the conditions imder which the plant lives and to the work which it performs. 

 In the second part the development of plants aiid their cljissiticaticm are treated 

 at some length. 



Causes determining the distribution of plants, C. Marechal {Ann. Gcm- 

 bloiix, 11 (1907), Xo. .9, ijp. 503-508). — A study is given of some of the causes 

 that determine the natural distribution of plants, and the author claims that 

 attention to the same factors would prove advantageous in introducing jtlants 

 into new regions. The principal factors are said to be elevation, temperature, 

 rainfall and humidity, and character of the soil. 



Factors affecting the seasonal activities of plants, D. T. MacDougal ( Plant 

 World, 10 (1907), Xo. 10, pp. 217-237. ptjs. 3). — An account is given of investi- 

 gations which are being carried on by the department of botanical research of 

 the Carnegie Institution. Gardens are located in alpine, sul)ali)iiie, and arid 

 situations near Tucson, Ariz., at which an interchange of plants has been made 

 to test the various factors influencing their seasonal activities. 



So far as the investigations have been pursued, the forces or factors affecting 

 vegetation are believed to be sim])le physical properties, and among the most 

 important are the thermal requirements of the plants. To determine the ther- 

 mal requirements of plants the author has adopted a system of measurement 

 in which the number of hour-degrees exposure is determined for the plant, 

 i)eginning with the winter solstice or with the germination of the seeds. 



The internal temperature of leaves under tropical insolation, A. M. Smith 

 (I'roc. Camhridgv I'hil. /S'oc, i.J (1907), Xo. 3. p. 296). — An abstract is given of a 

 jtaper connnunicated by the author giving the results of investigations relating 

 to the internal temperature of leaves. It was found that in still air, leaves 

 when placed in the sun possessed an internal temperature of 15° C. above the 

 surrounding air. In the shade the internal temi)erature varied from 1.5° below 

 to 4° above that of the surrounding air under different conditions. Breezes 

 of various strengths reduced the temperature from 2 to 10°. 



An attempt was made to estimate the magnitude of the cooling due to tran- 

 spiration, and of two sets of leaves differences averaging 2.5° were noted. 



It was found that red-brown coloring matter in the leaves tended to raise 

 the internal temi)erature i>f the leaf fi-om 2 to 4° above similar leaves which 

 were white or nearly so. Young colored leaves of thin texture, it is believed, 

 would be cooler than mature green leaves of the same six'cies, owing to more 

 rai)id loss of water, but the presence of red pigment causes their temperature 

 in most cases to be equal to or even higher than that of the mature leaves. 



The relation of phanerogamic parasites to nitrates, M. Mirande (Compt. 

 Rend. Acad. Sci. [Paris], 1J,5 (1907), Xo. 11, pp. 507-509) .—The author has 

 made a study of a number of phanerogamic parasites to determine if possible 

 the causes of their parasitism. He found an entire absence of nitrates in such 



