62 REPORTS OF INVESTIGATIONS AND PROJECTS. 



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A species of Orthocarpus (probably Orthocarpus purpurascens palmeri) 

 was found to be parasitic on the roots of about twenty herbaceous plants, on 

 which it exercises deleterious effects. 



Determination of Relative Water Soluble Contents of Salt-loving Plants. — 

 Dr. Cannon has ascertained that water extracts of the stems of species 

 growing in saline soils when tested with a Wheatstone bridge give a resist- 

 ance characteristic of the species, and that this resistance bears a definite 

 relation to that of the soil solution in which the plant customarily grows. 

 These results were confirmed by freezing tests, and also by analyses made 

 under the direction of Dr. W. J. Gies, of Columbia University. The readi- 

 ness with which the method may be applied suggests that it may be of great 

 value in distributional studies, such as that undertaken in connection with 

 the recession of the Salton Sea. 



Comparative Anatomical Studies of Hybrids. — An examination of the 

 origin, development, and final form of the tissues in hybrids and the parental 

 forms has been undertaken by Dr. Cannon. Such an investigation has not 

 as yet been made by modern morphological methods, and it is proposed to 

 carry it out with the exactness with which structures are surveyed in cyto- 

 logical work. It is within the range of possibility that this method may 

 evolve some feasible method of appreciating unit characters, or at least of 

 assisting in the evolution of this conception. Much of the material for this 

 work is being drawn from the plantations of Mr. Luther Burbank, and 

 includes Juglans, Papaver, and Solanum, as well as Oenothera from other 

 cultures. 



Physiology of Genetics — Influence of External Agents on Heredity. — A 

 comprehensive description has been previously given of a discovery by Dr. 

 D. T. MacDougal, made in 1905, that reagents of various kinds injected 

 into ovaries of seed-plants previous to fertilization induced breaks in heredity 

 by which some of the progeny derived from treated ovaries differed from the 

 parents in one or more characters. These experiments have been continued 

 and extended. Eighteen separate cases of such treatment, dealing with seven 

 species of five genera, are now under consideration. The earlier results 

 favored the assumption that the various reagents which had been used upon 

 the reproductive elements of plants with the effect described had induced 

 mutations or changes, which had been brought about^in the reduction divis- 

 ions leading to the formation of the egg-cells. In a study of the actual tech- 

 nique of the process, however, it was found that fluids of various kinds 

 injected into ovaries did not in any instance succeed in penetrating to the 

 embryo-sac or the egg-cell. The lining walls of the ovary, however, and the 

 endostomes through which the advancing pollen tubes must pass, were thor- 

 oughly permeated with the reagents, and would thus be in immediate contact 



