306 



SCIENCE. 



[N. S. Vol. XV. No. 373. 



sel (347) ; Micklejohn for Meiklejolin (285) ; 

 Laud for Land (21) ; and a few others even 

 more insignificant than the above. 



Volume II. will contain the remainder of 

 the text, from Le to Z, Addenda, full indices 

 of Greek, Latin, German, French, and Italian 

 terms, while volume III. will be devoted exclu- 

 sively to the general bibliographies. 



The Macmillan Company deserve great cred- 

 it for making such a publication possible and 

 for the manner in which they have performed 

 their part of the work. Frank Thilly. 



UNIVEESITTf OF MISSOURI. 



Report on a Botanical Survey of the Dismal 

 Swamp Region. By Thomas H. Kearney. 

 Contributions from the TJ. S. National Her- 

 barium, VI. : 6. Washington, 1901. 8vo. 

 Pp. 263, 12 plates, 39 figures and 2 maps. 

 The account of the Dismal Swamp vegeta- 

 tion here presented is both a valuable and 

 a thoroughly readable one. The subject is 

 handled from a number of viewpoints in such 

 a way that the reader obtains a well-rounded 

 conception of this particular vegetative cov- 

 ering and' of the interrelations of its constitu- 

 ents. The author is especially to be com- 

 mended for his careful inquiry into the causes 

 which produce the characteristic modifications 

 of the various vegetation forms, and for the 

 histological investigation of certain species, a 

 study which is altogether too rare as yet in 

 ecological research. 



Under 'Climate' the author discusses the 

 usual physical factors, temperature, sunshine, 

 humidity, precipitation and wind, though the 

 data unfortunately could not be secured for 

 the Swamp itself, but only for the neighbor- 

 ing meteorological stations, Norfolk and Cape 

 Henry. The prominent physiographic fea- 

 tures of the region, to which correspond, of 

 course, certain plant formations, are (1) the 

 beach and the dunes, (2) the salt marsh, (3) 

 the plain and (4) the swamps. A very impor- 

 tant discussion of the soils of these areas is 

 contributed to this portion by Mr. F. D. Gard- 

 ner, of the Division of Soils. 



In the treatment of the vegetative cover- 

 ing of the region, the author recognizes a 

 maritime and an inland group of formations. 



The former comprises the saltmarsh forma- 

 tion and the sand-strand formations. Under 

 the first are arranged a number of associations, 

 Spartina stricta association, Typha associa- 

 tion, Juncus association, which are, in fact, 

 alternating areas of the formation, in which 

 a certain facies or principal species is con- 

 trolling. Little attention is given to the rela- 

 tive importance of the species constituting the 

 formation, or to their sequence in time. The 

 most important physical conditions which 

 cause modification in saltmarsh plants are par- 

 tial submersion at high tide, a soft yielding 

 substratum and an excess of sodium chloride 

 in soil and water. The resulting modifica- 

 tions are largely concerned with the reduction 

 of the water loss, as is typical of halophytes, 

 by thickening the cuticle and the epidermal 

 walls, by the development of a dense hairy 

 covering, the sinking of the stomata, the con- 

 duplication of the leaf, or its partial or com- 

 plete reduction, the development of sueculency, 

 the presence of a considerable quantity of salts 

 in the cell sap, and the development of palisade 

 tissue. The value of the sheathing bases of the 

 old leaves in preventing the access of salt water 

 must be regarded as somewhat doubtful. The 

 consideration of the sand-strand vegetation is 

 clear and interesting. The beach and outer 

 dunes are characterized chiefly by Ammophila 

 arenaria, Uniola paniculata, Iva imhricata, 

 Panicum. amarum minus, Cahile edentula and 

 Salsola hali. The vegetation of the middle 

 dunes is much less open in nature. The most 

 characteristic feature is, perhaps, the dense, 

 often pure, thickets of Myrica carolinensis. 

 Other thickets are constituted by Prunus an- 

 gustifolia, P. serotina, Salix fluviatilis and 

 Cephalanthus occidenialis. The inner dunes 

 are wooded for the most part with Pinus tceda, 

 but a number of deciduous trees and shrubs, 

 Quercus, Diospyrus, Sassafras and Juniperus, 

 occur here also. An excellent analysis of the 

 effect of the mechanical action of the wind, 

 and of the effect of excessive transpiration 

 follows the floristic discussion. 



The non-hygrophile inland formations are 

 (1) forest formations, embracing the mixed 

 forest and the pine barrens, (2) cleared-land 

 formations, non-cultural and cultural, (3) 



