Floristik, Geographie, Systematik etc. 153 



weight of leaves inimersed in Na C] Solution and in sea-water, for 

 the same plants, examined at intcrvals of 3 hours for 27 hours, 

 with Observation s on the condition of plasmolysis. The general 

 conclusions include: Cavneüia, Syringa, Amin show first a decrease 

 in weight in the Solutions, which after 3 — 6 hours is succeeded by 

 a progressive increase (except Arum)\ Hex and Cavendishia show 

 progressive increase from time of first immersion. Leaves strongly 

 affected {Syringa, Arum) hy spraying with sea-water show the 

 greatest increase in Na Cl content in immersion experiments ■ 

 Variations in weight and increase of salt content are revealed. The 

 osmotic pressure of the cell sap is increased after 12-27 hours 

 immersion; Jeaf cells plasmolysed on first immersion, remain normal 

 after prolonged immersion. W. G. Smith. 



Macdougal. D. T., North American Deserts. (Geograph. 

 Journal, XXXIX. N»^ 2. p. 105-123. 8 plates. 1912.) 



The geographica! and botanical work of the Desert Laboratory 

 is here presented as a lecture Water suppl}^ is discussed as to 

 restricted precipitation, ratio of maximum and minimum annual 

 rainfall, etc, and the necessitj'' in botanical work for supplementing 

 existing meteorological statistics b}^ special observations. The mecha- 

 nism of the desert is illustrated mainly from the Salton and Otero 

 basins in the Colorado desert. Here during the progress ot 

 Irrigation works, observations have been made on the colonisation 

 of newly formed Islands produced in the reservoirs. There is also 

 a general review of the adaptations of desert xerophytes. The effect 

 of changes in climate and rainfall on the histor}^ and topography 

 of the desert and on its Vegetation is also dealt with. The plates 

 illustrate the features and Vegetation of these deserts. 



W. G. Smith. 



Malme, G. O. A. : n, Xyridaceae Friesianae. Beiträge zur Xyri- 

 dazeen- Flora Afrikas. (Svensk Bot. Tidskr. VI. p. 545 — 560. 

 1912.) 



Die Arbeit enthält die erste Bearbeitung des vom Dozenten an 

 der Universität Uppsala, Dr. Rob. E. Fries, während einer Reise 

 durch Afrika gesammelten Materials. Von den sechs Xyridazeen 

 stammen fünf aus Rhodesia, eine aus Kongo. Zwei neue Arten 

 und eine Varietät werden beschrieben, und zwar Xyri^ leptophylla 

 (aus Kongoj, Friesii und capensis Ty^uxih . v . näcrocephnla. .ausserdem 

 wird eine üebersicht zweier afrikanischer EuxyrisSl\r\i(ts> X. co)i- 

 ge>isis Büttner mit 11 Arten und X. Rehmayinii Alb. Nilss. mit 4 

 Arten) gegeben. G. Samuelsson -Uppsala . 



Nash, G. V., (Poales) Poaceae (pars.) (North American Flora 

 XVII. part 2. p. 99— 1Q6. September 18, 1912.) 



The present part contains the genera Arthraxou to Paspalmv, 

 inclusive. The following new species and new combinations are 

 included : Arthraxon Qiiartinianus [Alectoridia Qiiavtiniana A. Rieh.), 

 Schisachymcm Ganrnevi, S. inalacostachyuni Andvopogon malacosta- 

 chyus J. Presl), S. seniiglabrum , S. doiningen^e (Stveptachne domUi- 

 gensis Spreng), S. Silsmanni (RottboelUa Salsmanni Trin.), S. civra- 

 tutn [Aitdyopogon civratus Hack.), .S. Schottii [Andvopogon Schottii 



