1017] AGRICULTURAL BOTANY. 327 



fnr inspection in California during the fiscal year ended June 30, 1916. A list 

 of registered dealers and manufacturers of commercial fertilizers iu the State 

 is also given. 



Analyses of commercial fertilizers, P, H. Wessels et al. {Rhode Island 

 Sta. Insp. Bui., 1916, Oct., pp. 3-18). — This bulletin reports the results of actual 

 and guarantied analyses of 101 samples of fertilizers and fertilizing materials 

 collected for inspection in Rhode Island during 1916. "The absence of potash 

 in over one-half of the brands and the small amounts in those brands that do 

 carry potash are noticeable features of the fertilizer situation in 1916." 



AGRICULTURAL BOTANY. 



Department of botanical research, D. T. MacDougax (Carnegie Inst. Wash- 

 ington Year Book, llf {1915), pp. 55-106). — The groupings under vphich this work 

 by numerous investigators is reported include equipment ; photolysis, respira- 

 tion, hydration, and grovi'th; some special water relations of plants; envii'onic 

 relations; the Salton Sea and Mohave Desert regions; genetics; and various 

 special investigations. 



Some of the important results of this work considered as a whole are sum- 

 marized by stating that plant growth takes place at the expense of definite or 

 formative compounds, which are formed locally at a rate depending primarily 

 upon the influence of temperature on chemical velocity. The processes may 

 be masked or checked by imperfect respiration, enlargement depending upon 

 conditions affecting water absorption. Light breaks down the smothering 

 acids formed under incomplete respiration in cacti, thus facilitating the pro- 

 duction of formative material. Lessened acidity due to light action conditions 

 absorption of water, so that light may accelerate growth in two different ways. 

 Ausographic instruments have been improved and glass screens of specialized 

 transmissibility to light have been designed. The readily varying permeability 

 of protoplasm is referred to the interrelations of the disperse phase and the 

 disperse medium of the hydrophile emulsion colloids of which it is made up. 



Sunlight is found to cause changes in air as a result of which respiration 

 is highest on days of high solar radiation, less on cloudy days, and least at 

 night. Arrangements are in progress for measurements of electrical conditions 

 of the air under identical conditions. In a study of photosynthesis, formic 

 acid has been produced from solutions of carbon dioxid and potassium car- 

 bonate, and exposure of formic acid to sunlight and ultraviolet light has pro- 

 duced a substance giving the reactions of a sugar and capable of use as food 

 by green algse in darkness. 



Succulent plants under desiccation may show for a long time normal pro- 

 portions of water content, owing to coincident respiration or oxidation of solid 

 materials. While the proportion of nonreducing sugars in succulent plants 

 increased during one to six years of starvation, that of hydrolyzable carbo- 

 hydrates was decreased. The starvation phenomena, some of which persist for 

 several years after restoration of normal conditions, include hydrolysis of cell 

 walls, deformation and peripheral thickening of nuclei, and reduction of the 

 protoplast. Cell sap density of the desert plants is least in species native to 

 arroyos, and shows a scale ascending through those of canyons, rocky slopes, 

 and bajadas to those of saline areas. 



Plant successions which occupy an area originally bare finally culminate in 

 a formation the nature and permanence of which are determined by climate. 

 The history of terrestrial vegetation shows the four gi'eat eras, Eophytic, 

 Paleophytic. Mesophytic, and Cenophytic. The chief physical factors and their 



