AGRICULTURAL BOTANY. 221 



must take place, either of two flavoue molecules or of a flavone with one or more 

 molecules of an aromatic acid or phenol. 



This work, discontinued for lack of pure material, is expected to be carried 

 forward later and to throw liglit upon the constitution of anthocyanins. 



Distribution of stomata in some graminaceous seedlings, E. Zaepffel 

 (Compt. Rend. Acad. Sci. [Paris], 159 (.1914), No. 2, pp. 205-207; ahs. in Pharm. 

 Jour. [London], J,, ser., 39 (19U), No. 2652, p. 251; Qard. Chron., 3. ser., 56 

 (1914)- No. m6, p. 192). — Studies herein described regarding the location of 

 stomata on growing seedlings of wheat, oats, Panicum altissimum, and Pas- 

 palum stoJonifcrum in connection with localization of heliotropic response of the 

 different parts apparently tend to indicate that the region of the cotyledon in 

 which the stomata are most abundant is that of greatest heliotropic sensitivity. 



The transpiration current in plants, II, J. M. Janse (Jahrb. Wiss. Bot. 

 [Fringsheim], 52 {1913), No. 5, pp. 509-602, figs. 12; aT)S. in Bot. CentU., 123 

 (1913), No. 22, pp. 565, 566). — In continuance of a previous contribution (E. S. 

 R., 20, p. 324) dealing chiefly with water movements concerned in transpiration, 

 the author here discusses the apparent agency of the roots in this connection, 

 including the activity of endodermal cells as studied in vascular plants, views 

 of some other authors being given. The protoplast alone is credited with work 

 so done, the exact character of its action remaining unknown. 



The activities of the protoplasts in the cells concerned with water trans- 

 port, J. M. Janse (Jahrb. Wiss. Bot. [Pringsheim], 52 (1913), No. 5, pp. 603- 

 621, figs. 2). — Discussing data and conclusions above mentioned, the author 

 suggests the possible efficacy, in this connection, of a hydrolytic ferment in the 

 cell protoplasm; of ready reversibility in reactions (hydrolytic processes in 

 some cases requiring but little energy for their accomplishment or reversal) ; 

 of circulation in cell contents, bringing any given portion alternately to oppo- 

 site sides of the cell ; of synchronism between reversal of reaction and circula- 

 tion period; and of the above ferment as controlling the direction and extent 

 of the reaction even in the presence of considerable opposing forces. 



Osmotic pressure of some epiphytes and parasites, G. Senn (Verhandl. 

 Naturf. Gesell. Basel, 2/,. (1913), pp. i79-iS3).— This is a study of the osmotic 

 pressure of the cell sap of some parasites and epiphytes and of other plants 

 from the same localities. The results, as tabulated, tend to show that parasites 

 possess a higher osmotic pressure than their corresponding host plants, with 

 the possible exception of certain succulent species of both classes. 



The exudation of ice from stems of plants, W. W. Coblentz (Mo. Weather 

 Rev., Jt2 (19U), No. 8, pp. Jt90-Jt99, pis. 5, figs. 7).— In this paper the author 

 describes the formation of ice fringes upon the dittany (Cunila mariana). 

 The data given are based upon experiments and observations in the field and 

 laboratory, from which it appears that the ice foi-mation is not a function of 

 the surface condition of the stem. The ice was found to be formed on stems 

 without roots, and consequently it can not be considered as a result of hydro- 

 static pressure exerted by the roots. The ice fringe was found to be a com- 

 posite of a number of very thin ribbons, the composition of which is described. 

 It is considered that moisture is brought to the surface by capillary action, 

 and when the rate of supply to the surface is more rapid than the loss by 

 evaporation, ice is formed if the air is at a sufficiently low tempei'ature. 



Method of determining the life duration of seeds, W. Crocker and J. F. 

 Groves (Ahs. in Science, n. ser., J^O (1914), No. 1039, pp. 775. 776).— The authors 

 briefly outline various theories regarding the cause of the loss of vitality in 

 seeds and give a preliminary account of investigations to test the hypothesis 

 that the loss of vitality is due to a slow coagulation of cell proteins of the 



