1019] AGRICULTURAL BOTANY. 129 



t 



The author concludes that the "sourness" observed In these tests "is doe 

 to the neglect of Liming soils either originally deficient in Lime, e. g., coal meas- 

 ures or millstone grit, or from which the lime hus been washed out by rain, 

 e. g., limestone soils and many of the drift soils," and that "the Inevitable 

 loss of lime by Leaching is augmented (1) by the continuous use of acid fer- 

 tilizers, particularly sulphate of ammonia, and (2) by the presence of a smoky 

 and acid atmosphere." Methods of correcting the conditions observed by liin- 

 lng and the relative value of different forms of lime for the purpose are dis- 

 cussed. 



The recovery of ashes and their utilization in agriculture, A. I'iedallu 

 (Compt. Rend. Acad. Agr. France, J, (1918), Xo. 28, pp. 781-784; 00*. in Chem. 

 Abs., 12 (WIS), Xo. 20, pp. 2104, 2105).— The value of the ashes from French 

 army and Paris bakeries is discussed. It is stated that the ashes from the 

 army bakeries are used in the military gardens, but it Is estimated that 3 

 metric tons of ashes containing GGO lbs. of potash salts from the bakeries of 

 Paris are daily wasted. A table showing the ash, potash, phosphoric acid, and 

 manganese content of different kinds of wood is given. 



AGRICULTURAL BOTANY. 



Ecology, F. E. Ot.ements (Carnegie Inst. Washington Year Book, 1G (1917), 

 pp. 303-306). — Ecological studies during 1917 have centered mainly upon tlie 

 problems of grazing research, indicator plants, climatic cycles, climatic cycles 

 and succession in bad lands, and a system of permanent quadrates. 



Experimental evolution in a desert habitat, W. L. Towek (Carnegie Inst. 

 Washington Year Boole, 16 (1917), pp. 95-98). — It is stated that since any desert 

 environie complex represents probably the most diversified and variable set of 

 conditions that organisms are called upon to meet, none of the introduced spe- 

 cies could breed or survive without some aid in meeting sucli desert condi- 

 tions. The cultures of introduced species now at Tucson. Ariz., have achieved 

 a safe degree of adjustment to the problems they have met. Data are given 

 regarding adjustment tests to which plants were subjected and the genetic be- 

 havior of plants under observation and experiment. 



Vital statistics of desert plants, F. Shreve (Carnegie Inst. Washington Year 

 Book, 16 (1917), pp. 98-95). — A record has been carried on for seven years in 

 regard to the germinations and the fate of the seedlings of several species of 

 desert perennials on an area near the Desert Laboratory. Growth curves es- 

 tablished indicate that the largest individuals of Carnegiea gigantea are from 

 125 to 175 years old. Notes are given on germinations and survivals of the 

 various species which were planted in the observational area in question. 



It appears that the establishment of new individuals in the plant populations 

 of the desert is an extremely slow process, even for plants which are abundant 

 and characteristic. This fact leads to a striking conservatism as regards cer- 

 tain forms, this conservatism contrasting sharply with the rapid and abundant 

 development of annual forms during periods favorable thereto. 



Plant distribution on desert mountains, F. Shreve (Carnegie Inst. Washing- 

 ton Year Book, 16 (1917), pp. 92, 93).— An attempt is being made to study the 

 causes of the presence or absence of different species of plants in various 

 mountain regions. 



Rate of growth in relation to altitudinal conditions, F. Shreve (Carnegie 

 Inst. Washington Year Book, 16 (1917), pp. 89. 90). — From work prosecuted for 

 several years, mainly on the Santa Catalina Mountains, it appears that the 

 number of pine trees more than 10 cm. in diameter increases with an altitude 



