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



285. Frodin, John. Om fbrhallandet mellan berggrundens kalk-halt och de nordswenska 

 vaxternas utbredning [The relation between the lime content of the underlying rocks and the 

 distribution on the North Swedish species of plants]. [Swedish.] Bot. Notiser 1919: 139-147. 

 1919. — While it is true in general that certain plants prefer and are practically limited in 

 distribution to localities with underlying calcareous rocks, in many places lime-loving plants 

 occur in regions with underlying siliceous rocks. Especially in valleys calcareous stones and 

 gravel derived from neighboring calcareous formations may overlie the siliceous bed rock. 

 In places where the underlying rocks are calcareous, one may find lime-lovers poorly repre- 

 sented, because of masses of deposited siliceous sand and gravel. There is, therefore, need 

 of being careful and of not placing too much importance on the underlying rocks, as the upper 

 soil, gravel, or loose rocks may have a different content of lime. — P. A. Rydberg. 



286. Fuller, Geo. D. Units of vegetation and their classification. Bot. Gaz. 66: 385-388. 

 1918. — This paper embodies a critical review of some of the more recent articles making con- 

 tributions to the classification and nomenclature of the units of vegetation recognized by 

 ecologists. Moss is shown to have traced the early history of the subject, Gleason to have 

 emphasized the individualistic concept in contending that all phenomena of vegetation de- 

 pend upon the phenomena of the individual plant, while Clements has gone to the other 

 extreme in regarding the plant community as an organism or at least as directly comparable 

 to an organism. Clements has also elaborated a complex system of classification of plant 

 communities. Nichols is shown to have regarded the association as the fundamental unit 

 of vegetation and to have elaborated a logical classification based upon this unit. He has 

 also added a useful but abstract concept in the association-type to represent "a type of plant 

 association which is correlated with a given type of habitat." He is shown to have retained 

 the well known classification of Schimper by modifying the concepts to include the develop- 

 mental idea, and to have demonstrated the utility of his classification by applying it to the 

 analysis of the vegetation of Cape Breton Island. — Geo. D. Fuller. 



287. Ganong, W. F. Nichols's vegetation of northern Cape Breton. [Rev. of: Nichols. 

 George E. The vegetation of northern Cape Breton Island, Nova Scotia. Trans. Conn. 

 Acad. Arts and Sciences 22:249-467. 1918. See Bot. Absts. 1, Entry 833.] Rhodora 21: 

 171-172. 1919. — A review of Nichols's monograph. — James P. Poole. 



288. Harvey, LeRoy H. A coniferous sand dune in Cape Breton Island [Nova Scotia]. 

 Bot. Gaz. 51: 417-426. 8 fig. May, 1919. — An account of the only dune formation found in 

 this region. Three associations are described: (1) the middle beach; (2) the dune complex; 

 and (3) the salt marsh. The characteristic plants of each of these associations are listed. 

 In summarizing, the author states that "the purpose of the paper is to put on record several 

 facts of ecological interest: (1) a coniferous sand dune with Picea canadensis as its facies 

 located at the latitude of 47 degrees north; (2) Poa compressa as a sand binder; (3) abundant 

 layering in Picea canadensis and Abies balsamea; (4) the anomalous condition of a sand dune 

 moving seaward; (5*) a phenomenal development of Arceuthobium pusillum on Picea canaden- 

 sis; (6) the decisive value of ecological data in the interpretation of physiographic 

 phenomena." — P. D. Strausbaugh. 



289. Hepburn, Ivan P. Ecological notes on the mountainous portions of the Herschel 

 District [South Africa]. South African Jour. Nat. Hist. 1:210-223. 1919.— The mountains 

 of the Herschel District reach a height of 9000 feet, and the higher strata consist of Drakens- 

 berg lavas and basalt. The Cave sandstone strata reach a height of between 600 and 7000 

 feet, and probably strata of blue and red shale occur between the Cave sandstones. At a 

 lower level the red sandstone occurs. The annual rainfall varies from 23 to 40 inches. The 

 winter is cold. The spring is usually windy and dry and the early summer is often dry; the 

 late summer and autumn is the rainy season. There is no doubt that the influence of man 

 has increased and is still increasing the aridity of the country. This is very evident on the 

 mountains. The veld is mostly grassland but owing to overstocking, etc., the grass is in 



