Floristik, Geographie, Systematik etc. 189 



snowsurvey is that with the data acquired a selection of crops can 

 be made intelligently. Three cases of water supply may be con- 

 sidered by the irrigator: First, when an average amount maj' be 

 assured; second, an abundant supply; and third, an amount smaller 

 than the average. All of these states of supply have to be deter- 

 mined before the crops are planted, so that the crop can be adjusted 

 to the available water supply. Harshberger. 



Travis. W. G. and J. A. Wheldon. A new variety of Par- 

 nassia palustris. (Journ. Bot. 596. p. 254 — 257. 1912.) 



The authors of this paper consider the littoral form oi Parnassia 

 palustris as being worthy of varietal rank and thus have named it 

 P. palustris, var. condensata. It differs from the tj^pical palustris in 

 having numerous. low, stout flowering stems and large flowers and 

 also in growing in compact clumps. M. L. Green (Kew), 



Tuszon, J., A Fritillaria tenella alakjai. [Ueber die Formen 

 von Fritillaria tenella]. (Botanikai Közlemen\^ek. XI. 3/4. p. 131 — 

 135. Mit Fig. 1912. In magyar. Sprache.) 



Konstante Abweichungen sprechen dafür, dass drei Formen der 

 genannten Fritillaria zu unterscheiden sind: 



1. Forma montana (Hoppe) Tuszon, vom Mte Spaccato be- 

 schrieben, kalkliebend, nie in Begleitung einer anderen Form. 

 Verbreitung: Algier, Gallia, Austria (Süden), Hungaria (nur 

 Fiume), Montenegro, Rossia australis. 



2. Forma latifolia (Uechtr.) Tuszon. Exemplare von trockenen 

 felsigen Standorten ähneln sehr der vorigen Form. Verbreitung: 

 Dalmatia, Hungaria, Serbia, Graeca, Turcia, Romania. 



3. Forma Orsiniana (Pari.) Tuzson ist eine Apenninenpflanze. 

 Fritillaria tenella ist durch Uebergangsformen mit der Fr. involu- 

 crata All. der S.W.- Alpen, der südlichen Fr. messanensis Rafin., 

 der dalmatinischen F. gracilis A. et G. und der in I Strien und 

 auf dem Balkan einheimischen F. )ieglecta Pari, ziemlich eng ver- 

 bunden. Die zwei letzteren sind jedenfalls am richtigsten als For- 

 men der Fr. messanensis zu betrachten, wie es Beck (1904) bereits 

 mitgeteilt hat. Matouschek (Wien). 



Unstead, J. F., Climatic Limits of Wheat Cultivation with 

 special reference to North America. (Geograph. Journ. XXXIX. 

 pp. 347—366 and 421-441. 1912.) 



The present cultivation of wheat in N. America is mainh' 

 determined b}^ transport and other economic factors, but this inquir}- 

 is to determine the possible limits of cultivation as ascertained from 

 a study of climatic conditions. The paper is a useful demonstration 

 of geographica! methods applied to the study of distribution. The 

 control by heat conditions involves a brief discussion of the heat 

 and light requirments of plants. Diagrams are given showing the 

 actual distribution of wheat towards the north, and its relation to 

 such factors as accumulated temperature and light duration. Rainfall 

 conditions are likewise examined. The general conclusion is that a 

 great extension of the wheat area will take place over the northern 

 cold and the western semi-arid lands of N. America. Also the 



