VIII] THE MAIDEN HAIR TREE 127 



and of the Ginkgoales supplies overwhelming testi- 

 mony to the tenacity of life with which the INIaiden 

 Hair tree has persisted through the ages. 



It was pointed out in the account of the past 

 history of Araucaria that the records obtained from 

 Palaeozoic rocks, while affording evidence of the 

 existence of Carboniferous and Permian genera un- 

 doubtedly allied to the living species, do not enable 

 us to speak with certainty as to the precise degree of 

 affinity. Similarly, Palaeozoic leaves have been de- 

 scribed as representatives of the class of which Ginkgo 

 is the sole survivor, but the evidence on which this 

 relationship is assumed is by no means conclusive. 



The generic name Psygmophyllum has been applied 

 to some impressions of Ginkgo-like leaves discovered 

 in the Upper Devonian rocks of Bear Island, a small 

 remnant of land in the Arctic circle, which has fur- 

 nished valuable information as to the composition of 

 one of the oldest floras of which satisfactory remains 

 have been found. Other examples of these lobed, 

 wedge-shaped leaves are recorded fi'om Carbonifer- 

 ous rocks in Germany, France, and elsewhere ; from 

 Permian strata in the east of Russia and from Palaeo- 

 zoic beds in Cape Colony and Kashmir. A relationship 

 between Psygmophyllum and Ginkgo is, however, by 

 no means established and rests solely on a resemblance 

 in the form of the leaves. The close correspondence in 

 form and venation between some leaves from Permian 



