XL] 



GINKGOITES 



17 



The leaves of Ginkgo digitata have a long slender petiole (fig. 634) ; 

 the lamina is semiorbicuiar or obcuneate, entire, or more or less 

 deeply divided into equal lobes, or irregularly divided into several 



A. 



B. 



C. 



D. 



E. 



F. 



G. 



H. 



I. 



J. 



K. 



L. 



M. 



K 



FIG. 635. Ginkgoite*. ( nat. size.) 

 Ginkgoites adiantoides, Tertiary, Island of Mull. 

 G. pluri partita, Wealden, North Germany (after Schenk). 

 G. digitata, Jurassic, Japan (after Yokoyama). 

 G. digitata var. Huttoni, Jurassic, Australia (after Stirling). 

 G. sibiri'M, Jurassic, Siberia (after Heer). 

 G. digitata, Jurassic, Turkestan. 



G. mnltinervis, Lower Cretaceous, Greenland (after Heer). 

 G. digitata, Jurassic, Oregon (after Fontaine). 

 G. digitata, Jurassic. Yorkshire. 

 G. digitata, Jurassic, Scotland (after Stopes). 



G. digitata, Jurassic (or Wealden), Franz Josef Land (after Nathorst). 

 G. moltenensis, Rhaetic, South Africa. 

 G. digitata, Jurassic (or Wealden), Spitsbergen (after Heer). 



. 



segments ; the number and size of the segments and the form of 

 their distal ends, truncate or obtuse, vary within wide limits 

 (figs. 635, 637, 639, etc.). Numerous dichotomously branched 



2 



s. iv 



