VIII] THE MAIDEN HAIR TREE 129 



Baiera ; this name is applied to wedge-shaped leaves 

 with a slender stalk similar in shape and venation to 

 those of- Ginkgo, but differing in the greater number 

 and smaller breadth of the segments. Between the 

 deeply dissected leaf of a typical Baiera with its 

 narrow linear lobes and the entire or broadly lobed 

 leaf of a Ginkgo there are many connecting links, and 

 to some specimens either name might be applied with 

 equal fitness. Examples of Baiera leaves, in some 

 cases associated with fragments of reproductive organs, 

 are recorded from Rhaetic rocks of France, the south 

 of Sweden, Tonkin, Chili, the Argentine, Xorth America, 

 South Africa, and from other regions. There is abun- 

 dant evidence pointing to the almost world-wide 

 distribution of the Ginkgoales, as represented more 

 especially by Baiera, in the older :\Iesozoic floras. In 

 the later Jurassic rocks of Yorkshire true Ginkgo 

 leaves as well as those of the Baiera type are fairly 

 common ; with the leaves have been found pieces 

 of male and female flowers. Ginkgo and Baiera 

 have been described from Jurassic rocks of Germany, 

 France, Russia, Bornholm, and elsewhere in Europe ; 

 they occur abundantly in Middle Jurassic rocks in 

 northern Siberia, and are represented in the Juras- 

 sic floras of Franz Josef Land, the East Coast of 

 Greenland, and Spitzbergen (Fig. 20). The abund- 

 ance of Ginkgo and Baiera leaves associated with 

 male flowers and seeds discovered in Jurassic rocks, 



S. a 



