CHAPTER XLIL 



GENERA OF UNCERTAIN POSITION. 



In this section are included several Palaeozoic genera mos 

 which have been assigned to the Ginkgoales on evidence which i 

 most cases is wholly inadequate. 



Probably the oldest specimens referred to the Ginkgoales are 

 some imperfect leaves from Middle Devonian rocks in Bohemia 

 described by Potonie and Bernard as Barrandeina Dusliana 

 (Krejci) 1 , but there is no evidence of affinity to this or to any othe 

 class of plants. 



GLOTTOPHYLLUM. Zalessky. 



This designation has recently been proposed by Zalessky 2 fo 

 Schmalhausen's Permian species Ginkgo cuneata which has n 

 substantial claim to be regarded as generically identical with 

 Ginkgo biloba. Zalessky considers that it may belong to the 

 Ginkgoales though the available data hardly justify more than a 

 suggestion of possible relationship. 



Glottophyllum cuneatum (Schmalhausen). 



A Permian species from the Altai mountains 3 represented 

 obovate spathulate leaf 11 cm. long and 4 cm. broad with a compara- 

 tively long * stalk ' consisting of a narrow portion of the lamina : 

 the lamina is traversed by slightly spreading veins about 1 mm. 

 apart. In form this leaf resembles the genus Eretmophyllum* (cf. 

 fig. 658) and may be a species of that genus, but in the absence 

 of any information with regard to the epidermal features it is 

 inadvisable to adopt a name implying affinity to the Ginkgoales. 



1 Potonie and Bernard (04) p. 45. 



2 Zalessky (12 2 ) p. 28 (footnote). 



3 Schmalhausen (79) A. p. 34, PI. iv. fig. 5 



4 Thomas, H. H. (13). 



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