Morphologie. — Physiologie. 297 



Pechoutre , F., Developpement du tegument de 



I'ovule et de la graine du Geum urbanum L. (Journal 



de Botanique. Annee XV. 1901.) 



L'ovule de Geum urbanum n'a qu'un seul tegument alors que celui 

 du Dryas octopetala L. en a deux. La comparaison du developpement 

 de l'appareil tegumentaire dans ces deux especes amene l'auteur ä 

 supposer „qu'il y a chez le Geum avortement du tegument interne". Ca 

 dernier y serait cependant represente ä l'etat de vestige par le cloisonne- 

 ments de quelques cellules epidermiques. Lignier (Caen). 



Mac DouGAL, D. T. , A practical text-book of plant 

 physiology. XIV. 352 pp. with 159 figures in text. 

 New-York, London and Bombay (Longmans, Green and Co.) 

 1901. 



A discussion of the principles of the subject, with directions 

 ■for the principal phenomena of the physiology of the plant, and 

 details of experimental methods suitable for the exact analyses 

 requisite in research work. I. Nature and relation of an 

 organism. II. Relations of plants to mechanical forces. III. 

 Influenae of chemicals upon plants. IV. Relations of plants to 

 water. V. Relations of plants to gravitation. VI. Relations of 

 plants to temperature. VII. Relations of plants to electricity 

 and other forms of energy. VIII. Relations of plants to light. 

 IX. Composition of the body. X. Exchanges and movements 

 of fluids. XI. Nutritive metabolism. XII. Respiration, fer- 

 mentation and digestion. XIII. Growth. XIV. Reproduction. 



Mac Dougal. 



Johnson, T. C, Intramolecular respiration. (Botanical 

 Gazette. XXXII. 1901. p. 303—304.) 



A Single test with germinating seeds of Japanese buck- 

 wheat. Mac Dougal. 



•COPELAND, E. B., Meissner on evergreen needles. (Botani- 

 cal Gazette. XXXII. 1901. p. 356—359. Fig. 1.) 



Some data concerning the influenae of various external 

 factors upon the growth of coniferous leaves and a discussion 

 of Meissner 's results are given. Mac Dougal. 



Baranetzky, J., lieber die Ursachen, welche die Rich- 

 tung der Aeste der Baum- und Straucharten be- 

 dingen. (Flora. Ergänzungsband. 1901. p. 138 — 239. 

 Mit 20 Textabbildungen.) 



Neuere Arbeiten, welche dieses Thema erschöpfend be- 

 handeln, lagen nicht vor. Man betrachtete die Baumäste ge- 

 wöhnlich als plagiotrope Organe, deren Lage durch den Trans- 

 versalgeotropismus bedingt würde. Thatsächlich sind aber die 

 Ursachen der Astrichtungen etwas complicirter Art. Die 

 Resultate des ersten Capitels, das über „die Eigenschaft der 



