BOOKS AND CURRENT LITERATURE 



The Wilcox Flora of the Lower Eocene. — The flora of the Wil- 

 cox formations, recently monographed by Berry/ is one of unusual 

 interest to botanists as well as to geologists. This is due to the care- 

 ful manner in which the flora has been studied and described by Berry, 

 and to the fact that it is one of the largest floras that has been recorded 

 from a single horizon in a comparatively restricted area. It com- 

 prises 128 genera in 59 families and 33 orders, more than 94% of which 

 are Angiosperms. Floristically, the Wilcox flora resembles that of 

 parts of tropical and subtropical America, particularh' the strand veg- 

 etation of the Caribbean coast from Central America to northern 

 Brazil. In addition, the Wilcox flora contains a number of genera, 

 such as Artocarpus, Nipa, Cinnamomuni, Banksia, etc., which have- 

 at present an oriental distribution. 



As is well known, there has been in the past considerable contro- 

 versy in regard to the value of foliar characters as diagnostic criteria. 

 The instability of the gross or superficial characters of leaves has been 

 emphasized by many taxonomists, and by a number of morphologis"ts 

 who have desired to bring into the limelight the conservatism of in- 

 ternal structures. For example, Bentham,- after making a very com- 

 prehensive study of the Proteaceae, stated in regard to detached 

 leaves, "I do not know of a single one which, in outline or venation, 

 is exclusively characteristic of the order, or of any one of its genera.' 

 Seward,^ the well known English paleobotanist, considers that, "Vena- 

 tion characters must be used with care even in determining classes or 

 groups, and with still greater reserve if relied on as family or generic 

 tests." 



In view of supposed difficulties in identifying plants by the impres- 

 sions of their leaves, the following conclusions of Berry are of consider- 

 able interest: "Many botanists love to dwell on the temerity of the 

 paleobotanists in determining species from impressions of leaves. I 



1 Berr3% E. W., The Lower Eocene Floras of Southeastern North America. 

 Professional Paper 91, U. S. Geol. Survey, pp. 481, pis. 116, Washington, 1916. 



2 Bentham, G., Presidential Address. Linn. Soc, p. 17, London, 1870. 



3 Seward, A. C, Fossil Plants, 1: 99, Cambridge, 1898. ' 



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