DEPARTMENT OF BOTANICAL RESEARCH. 77 



hibernation the extracted parent forms, however, are entirely or nearly 

 eliminated, and only the heterozygous individuals have thus far been 

 able to breed in F2 or F3, and these gradually become weaker and are 

 finally exterminated. In the future we shall try to temper the rigor 

 of the desert conditions during the initial generations, and perhaps by 

 the gradual transition into the desert complex it may be possible to 

 bring about the adaptation of these inhabitants of the moist regions to 

 desert conditions, thus getting important information concerning the 

 processes of adaptation and of the water relations of the inhabitants of 

 arid and moist environmental complexes. 



The spherical form of atmometer noted in the reports for 1912 and 

 1913 continues to justify its adoption for use in these experiments, and 

 the methods of cleaning and operation show that the instrument is 

 fully as sensitive and reliable as a thermometer. Our permanent black 

 cups are specially sensitive, tests at Chicago showing them to be sensi- 

 tive to the passing of the lightest cloud or even of the shadow cast by 

 one's hat. It is hoped that these instruments can be made available 

 for general use within the year. 



The general oversight and care of the experiments has been continued 

 through the year by Mr. J. G. Sinclair. 



The Intra-Vitam Absorption of Methylene Blue in the Ovules of 

 Scrophularia, by Francis E. Lloyd. 



In order to determine the probable course of absorption consequent 

 upon the injection of stimulatory or other reagents into the living 

 ovaries of seed plants, recourse was had to the following of the relative 

 rates of intra-vitam absorption of methylene blue by the various ovular 

 structures. Two procedures were employed, that of the usual ovarial 

 injection of a 1 to 1,000 solution used by Dr. D. T. MacDougal, and 

 that of allowing sections of the living ovary with attached ovules to 

 lie in weak solutions of the stain. The evidence shows that there is a 

 very definite localization of absorption whereby the reagent in question 

 reaches the egg-apparatus of Scrophularia. The small ovule is com- 

 posed chiefly of the single integument, the innermost layer of which, 

 known as the tapetum, constitutes a special tissue lining a slender 

 cylindrical cavity in which lies the embrj^o-sac. The end containing 

 the egg-apparatus tapers to form a closed micropyle, while the anti- 

 podal end is embedded in the small chalaza, which is peculiar in having 

 cells with thickened walls. (Fig. 3.) 



Fertilization is accomplished within 4 to 8 hours after pollination. 

 The course of the pollen-tube is as follows: from the style, the tubes 

 pass down between the placental plates (w^hich are free from each other 

 in the upper part of the ovary) and along the surfaces of the placentas 



