40 ECOLOGY, PLANT GEOGRAPHY [Bot. Absts., Vol. IV 



FORMATIONS, ASSOCIATIONS 



274. Armitage, Eleanora. On the habitats and frequencies of some Madeira bryo- 

 phytes. Jour. Ecol. 6:220-225. 1918. — A brief account of the bryophyte communities at 

 various elevations on the southern side of the island of Madeira. About 170 species are 

 listed as characteristic of various habitats. — G. E. Nichols. 



275. Arrhenius, Olof. Forsok till en ny metod for analys av vaxtsamhallen. [Experi- 

 ments relating to a new method of analyzing plant associations.] Svensk. Bot. Tidskr. [Stock- 

 holm] 13 : 1-20. 1919. — The author describes and illustrates a method which he has worked 

 out for quickly analyzing plant associations. He has used it in about one hundred cases 

 with good results, though he considers it still in the experimental stage. Its chief value is 

 its ready adaptability to field use. — W. W. Gilbert. 



276. Beauverd, Gustave. Excursions phytogeographiques aux environs de Viege et Zer- 

 matt (Valais). [Phytogeographic excursions to the vicinity of Viege and Zermatt (Switzerland).] 

 Bull. Soc. Bot. Geneve 10: 259-284. 1918. — A comparative study of the spring subalpine flora 

 in the vicinity of Zermatt leads to an ecological classification in which the flora may be con- 

 sidered as represented by three phases. The first flowering plants to dominate the arti- 

 ficial prairies are: Trollius europasus, Melandrium roseum, Geranium silvaticum, and Nar- 

 cissus poeticus which was possibly introduced. In the scrub, Juniperus sabina is accom- 

 panied by different species of Artemisia, Achillea, Astragalus and Oxytropis. Juniperus 

 commune, Primus mahaleb, and Berberis vulgaris are generally frequent. The lower forests 

 consist mainly of pine, spruce, birch and larch with Crataegus, a little Quercus and Acer 

 campestre. Pinus montana, Betula pubescens, Picea excelsa, and Larix decidua make up the 

 middle forests fringed with Pinus cembra, Alnus viridis, and sometimes different species of 

 Salix. With the disappearance of Pinus montana and Picea excelsa the upper forests are 

 characterizied by a pure formations of firs. — W. H. Emig. 



277. Bews, J. W. The grasses and grasslands of South Africa. VI + 161 p. 24 fig- 

 P. Davis & Sons, Ltd.: Pietermaritzburg, 1918.— See Bot. Absts. 2, Entry 7; 3, Entry 1287. 

 Also Nature 103:62. Rev. by Fuller in Bot. Gaz. 67:370, and by W. G. Smith in Jour. 

 Ecol. 7:84-87. 



278. Bouget, Joseph. De l'influence des neiges sur la repartition des differents vegetaux 

 a mime altitude dans les zones elevees des Pyrenees. [The influence of snow on the distribu- 

 tion of different plants at the same altitude in the elevated zones of the Pyrenees.] Rev. G6n. 

 Bot. 30: 305-320. Oct., 1918. The author discusses some facts concerning plant distribution 

 on the north slope of the central Pyrenees, on the basis of observations made during a period 

 of twenty-five years. Three levels are chosen in order to facilitate presentation: one at 1900, 

 a second at 2500, and a third at 2800 meters. Lists of the plants found in places of more 

 marked relief, and those growing in depressions at these respective altitudes are given. An 

 attempt is made to account for this grouping of the vegetation, each group presenting its 

 own peculiar floral composition. Reference is also made to the practical application of the 

 facts observed in the problem of reforestation. Conclusions are as follows: "(1) the distri- 

 bution of plants in the elevated places of the mountains is strongly influenced by the relief 

 of the surface and by the length of time it is covered with snow. At a given altitude, with a 

 given exposure, and upon soil of the same nature, the vegetation is xerophilous upon the ridges 

 with some woody and herbaceous plants; while it is essentially hygrophilous in the low places 

 with plants exclusively herbaceous. Between these extreme cases there exists an interme- 

 diate vegetation the nature of which is in direct accord with the contour of the land. (2) 

 The exclusively herbaceous flora of the depressions where the snow remains for a long time is 

 composed of a curious mixture of alpine and lowland plants, all however hydrophilous. 

 (3) The upper limits of the forests are directly determined by these influences, that is by the 

 relief of the soil. The trees always occur at a higher altitude on the ridges than in the low 

 places. Abies pcclinata, for example, never ascends above 1800 meters except upon the 



