176 



SCIENCE 



[N. S. Vol. XLI. No. 1048 



Since non-reducing, hydrolyzable sugars are pres- 

 ent in many plant tissues and are subject to wide 

 variation in the same tissue, the above described 

 method in unmodified form is not reliable. 



Electrolytic Determination of Exosmosis from the 

 Soots of Anesthetized Plants: M. C. Mekbill. 

 Subjecting growing plants of Fisum sativum to 

 the iniluenee of illuminating gas and ether vapor 

 causes a marked exosmosis from the roots. The 

 plants were grown for several days in full nutrient 

 solution and, after thorough rinsing of the roots, 

 were placed in redistilled water whose specific con- 

 ductivity was approximately .000002. Immedi- 

 ately afterward the plants were subjected for 

 varying periods to the gas or vapor, and the effect 

 determined by frequent measurements of the con- 

 ductivity of the water as contrasted with that in 

 which control plants were placed and also by sub- 

 sequently growing fresh seedlings in the water. 



The exposures were made in all cases under bell 

 jars. Where the roots were exposed directly to 

 the anesthetics the resulting exosmosis was more 

 rapid than where the roots were kept in the water 

 during the exposure. In the former case the root 

 turgor decreased greatly, while in the latter case 

 the tops were affected, ibut the roots remained nor- 

 mal in appearance even though the exosmosis was 

 abundant, thus indicating a disappearance of min- 

 eral nutrients from the tops. With older plants 

 the increased conductivity was less than with 

 younger plants, thereby indicating greater resist- 

 ance to the anesthetics. 



Some Relations of Plants to Distilled Water and 

 Certain Dilute Toxic Solutions: M. C. Merrill. 

 A careful determination was made of the inter- 

 val during which Pisum sativum seedlings could 

 grow in redistilled water and in certain toxic so- 

 lutions, and then recover when later placed in full 

 nutrient solution. The benefits to be derived 

 from renewing the distilled water every four days, 

 as contrasted with the condition where it was not 

 renewed, were evidenced in most cases by better 

 growth in the distilled water or greater recovery 

 in the full nutrient solution. Horse beans (Vicia 

 faha) were more marked than Pisum sativum in 

 their behavior toward the renewal of the distilled 

 water, those in which the distilled water was re- 

 newed showing more than double the growth. Bac- 

 terial and fungous action is undoubtedly an im- 

 portant factor, as demonstrated by the effect of 

 boiling the water. The evidence indicates that 

 there are several factors entering into the so- 

 called harmful action of distilled water. Striking 



changes in the conductivity of the distilled water 

 were found when plants were placed in it during 

 various stages and conditions of growth. 



Bevegetation of Abandoned Soadways in Eastern 



Colorado: H. L. Shantz. 



A roadway consisted of a trail formed by driv- 

 ing repeatedly over the short grass sod. After a 

 few years a new road was formed at the side of 

 the old trail. In this way many roads were 

 formed and successively abandoned. The plant 

 succession on these abandoned roadways consists 

 of an early and late ruderal association followed 

 by either the Artemisia-Gutierrezia association or 

 the wire-grass association. The final stage or 

 Grama-Buffalo grass association becomes estab- 

 lished in from twenty to thirty years. 



Is the Flora of the Prairie and Steppe of Arctic 



Origin?: B. Shimek. 



The conclusion of the paper is opposed to the 

 widely prevalent conception that the flora of the 

 steppes (and incidentally of the prairies) is of 

 Arctic origin, and that the "steppe" condition is 

 an evidence of a colder climate. The fact that 

 certain plants (and, even more conspicuously, cer- 

 tain animals), more particularly in Europe, are 

 now found only in the far north, but formerly ex- 

 isted much farther south, is not regarded as evi- 

 dence of a much colder earlier climate in these 

 more southerly regions, for we probably have to 

 deal here with remnants of a formerly widespread 

 flora and fauna now largely restricted through 

 man 'a influence. 



Comparisons are made of plant lists showing 

 distribution in both Europe and North America, 

 and on this basis, and on the basis of structural 

 adaptation to habitat, and habit, the conclusion is 

 drawn that the plants of these treeless areas 

 reached their present state under the influence of 

 dry conditions, and that their present distribution. 

 was accomplished by advance from regions south 

 of the glacial limit. 



Growth-forms of the Flora of New YorTc and 



Vicinity: Norman Taylor. 



The study of climate, through the study of the 

 vegetative response to it, involved the dividing of 

 all vegetation into 10 or 12 different categories. 

 Eaunkiaer has called these ' ' growth-forms, ' ' which 

 are based on the amount and kind of protection, 

 exhibited by the growing or perennating shoots 

 during the winter or critical season. The useful- 

 ness of the method lies in its value as a basis of 

 comparison between different floras, different ele- 

 ments of the same flora, and even smaller cate- 



