468 SCIENCE PROGRESS. 



striking manner by Mesozoic floras of a slightly different age, 

 is the wide distribution and abundance in the European 

 vegetation of species of the Gleichenia type. Species of 

 other genera similarly throw light upon the wider distribu- 

 tion and greater abundance of ferns now confined to the 

 tropics. 



The chief interest connected with the Wealden cy- 

 cadean flora is the abundance of the Bennettitese, plants 

 which flourished for only a short period during the Jurassic 

 epoch and the beginning of the Cretaceous period. This is 

 not the place to describe in detail the various morphological 

 features of the genus Bennettites ; 1 it is a type of plant 

 which had no doubt a common ancestry with the true 

 Cycads, and in the structure of its female flowers displayed 

 a nearer approach to angiospermous characters than is 

 the case in the reproductive organs of the Cycads. The 

 Bennettitese probably represent a branch of the cycadean 

 phylum, which cannot be traced to any direct offshoot 

 among existing types. 



BIBLIOGRAPHY. 



[For a more complete list of works relating to the Wealden 

 flora reference should be made to the bibliography in vols. i. and 

 ii. of the British Museum Catalogue of Wealden Plants, published in 

 1894 an d 1895. Prof. Zeiller's extremely good Revue des Travaux 

 de Pale'ontologie Vegetale publics dans le cours des Annees 1893-96, 

 contains references to the more recent publications.] 



Baker, J. G. A Summary of the new Ferns which have been 



discovered or described since 1874. Annals Bot., vol. v., p. 



181, 1891. 

 Barber, C. A. Cupressinoxylon vectense; a Fossil Conifer from the 



Lower Greensand of Shanklin, in the Isle of Wight. Annals 



Bot., vol. xii., p. 329, 1898. 

 CAPELLINI, G., and Solms-Laubach, Graf ZU. I Tronchi di 



Bennettitee dei musei italiani. Mem. R. accad. Sci. inst. 



Bologna [5], vol. ii., p. 161, 1891. 



1 In addition to the well-known memoirs by Carruthers, Solms-Laubach 

 and Lignier, mention may be made of a still more recent description 

 of Bennettites by Fliche {vide Bibliography). 



