jgig] CURRENT LITERATURE 483 



Lauraceae, Leguminosae, and Celastraceae. The members of the IMyrtales 

 also were probably dwellers in the dry or wet strand. Many of the plants 

 probably demanded a heavy rainfall, with emphasis on the warm temperate 

 rain forest t>'pes. Such areas as southern Japan or northern New Zealand 

 offer many points of comparison with the Upper Cretaceous floras of the 

 coastal plain. The climate then was equable within the hmits embraced 

 between warm temperate and subtropical. The floras of the Eutaw and 

 Ripley formations are treated similarly by Berry, who concludes the intro- 

 ductory portion of the monograph with a consideration of correlations and 

 the presentation of a table of the distribution of the three floras minutely 

 analyzed. The work ends with a detailed account of the fossil plants, with the 

 description of several new species illustrated with ^^ fine plates of geological 

 scenery and fossil plants. — J. W. Harshberger. 



Wood structure and conductivity. — Holmes* has made a quantitative 

 study of the anatomy of ash wood, attention being directed chiefly to the size 

 and proportion of the water-conducting elements in different parts of a shoot. 

 As in the case of the hazel wood previously investigated by this author, year 

 old ash shoots were selected, most of the specimens being typical coppice, 

 stool shoots, long, thick, and unbranched. His results are presented in graph- 

 ical form, a set of curves being constructed for each shoot. 



Curve A gives the variation in area of the wood at selected levels along 

 each shoot. Curve B, representing the absolute conductivity or total volume 

 of transmitted water, is obtained by calculating the total number of vessels 

 in a transverse section at the different levels- and the average diameter of the 

 cavities of these vessels. This curve shows a decline from the base to the 

 apex of the shoot. Curve C serves as a measure of the specific (or relative) 

 conductivity for water, or the percentage of wood area occupied by vessel 

 cavities. In general this curve rises and then falls, the upper (younger) part 

 of the stem being a better conductor of water per unit area than that nearer 

 the base. An increase in the proportion of fibers in any part of the shoot, 

 usually at the base where mechanical support is necessary, quite obviously 

 lowers the specific conductivity in that portion of the stem. 



In comparing the ash with the hazel wood, the writer finds in both a fall 

 in absolute conductivity and a rise in specific conductivity from the base of 

 the shoot to its apex, but the figures for specific conductivity are much higher 

 in hazel than in ash, due to its greater number of conducting elements per unit 

 area. 



In the main, these results agree with those obtained by Farmer' for the 

 two kinds of wood in question, in his extensive investigations for determining 



■ * Holmes, M. G., Observations on the anatomy of ash-wood with reference to 

 water-conductivity. Ann. Botany 33:255-264. ^g5. 7. 1919. 



9 Farmer, J. B., On the quantitative differences in the water-conductivity of the 

 wood in trees and shrubs. Proc. Roy. Soc. 90: 1918. 



