448 Floristik etc. — Pflanzenchemie. — Angewandte Botanik. 



Wernham, H. F., New Rubmceae (vom Tropical America. III. 

 (Journ. Bot. LI. p. 320—324. 1913.) 



The new species described are: Portlandia involucrata, P. uligi- 

 nosa, Aiseis Gardneri, Cosmibnena gorgonensis , C. gardenioides , Chio- 

 cocca enibescens, C. pulcherrima, C. capitata, C. pachxphylla. 



M. L. Green (Kew). 



Dixon, H. H. and Wo R. G. Atkins. The Extraction of 

 Zymase by Means of Liquid Air. (Notes Bot. School Trinity 

 Coli. Dublin. II. p. 177—184. 1913.) 



The authors have shown that sap may be extracted from various 

 plant-organs without change of concentration by pressure after the 

 organ was immersed for a few minutes in liquid air (Bot. Centralbl. 

 cm. p. 191); apparently the intense cold renders the protoplasm 

 permeable, and the pressure forces out the Solution from the 

 vacuoles unchanged. This suggested the probability that similar 

 exposure of the yeast-cell would render its protoplasm permeable^ 

 so that the zymase and other endo-enzymes would be free to 

 escape; and this surmise has been confirmed by experiment. The 

 liquid air method of extracting zymase has the advantage of being 

 very rapid, the time for changes taking place in the enzyme is 

 reduced to a minimum. F. Cavers. 



Haas, P. and T. G. HilL An Introduction to the Chemis- 

 try of Plant Products. (London: Longmans and Company. 

 401 pp. Price 7 sh. 6 d. net 1913.) 



A general account of the chief chemical substances occurring 

 in plants, treated from the chemical and physiological points of 

 view, with notes on their preparation and chemical and physical 

 properties. The book is specially written for plant physiologists, and 

 the authors have avoided a too technical method of treatment such 

 as might have made the work less suitable for botanists without a 

 very thorough knowledge of chemistry. The chapters are devoted 

 to fats, waxes and Phosphatides; carbohydrates; glucosides; tannins; 

 pigments; nitrogen bases; colloids; proteins; enzymes. Throughout 

 the book the result of recent research are incorporated in the 

 descriptions ot the various substances dealt with. F. Cavers. 



Parish, S. B., Plants introduced into a Desert Valley as 

 a Result of Irrigation. (The Plant World. XVI. p. 275—280. 

 Oct. 1913.) 



The author describes the introduction of various weeds into the 

 Imperial Valley on the borders of the Colorado Desert. He 

 finds that the worst weed of the Valley is Aster spinosus, that 

 Echinochloa colonna is frequent in alfalfa fields and that Atriplex 

 semibaccata is a ruderal weed. The running mallow, Sida hederacea 

 is ver3'- difficult to eradicate. He notes the common weeds of Cali- 

 fornia not observed in the Valley. Harshberger. 



A-UBgegeben : 38 -A.pril 1914. 



Verlag von Gustav Fischer in Jena. 

 Buchdruckerei A. W. Sijthoff in Leiden, 



