PaOTOPIEEIS. 71 



bearing strata of Bohemia, from which Sternberg's specimen was 

 obtained, were of Cenomaniaa age, and this led Hear to correct his 

 previous statement as to the age of the Disco Island plant beds.' 



It is to Cotta'' that we are indebted for the earliest information 

 as to the minute structure of the genus Protopteris. In 1836 he 

 described in detail the anatomy of a tree-fern stem, afterwards 

 called P. Cotteana, which was found in a boulder in Saxony, but 

 considered to have originally come from Bohemia ; this plant 

 agrees very closely with the common form P. punctata. The 

 generic name Caulopteris, Lindley and Hutton, is substituted for 

 Protopteris in Goppert's "Eossilen Farrnkrauter." ' Carruthers* 

 also prefers Lindley and Hutton's genus as being older than Presl's 

 Protopteris, and more suitable for such tree-fern stems. In Corda's 

 classic work * Sternberg's specimen is further described, and com- 

 pared to the Cyatheacea ; the original name, P. punctata, being 

 replaced by that of P. Sternhergii. The name Protopteris was 

 originally given to a tree-fern stem possessing a well-defined 

 character in the form of its leaf -trace bundle ; on the other hand 

 the generic term Caulopteris was applied to a specimen on which 

 no useful or precise definition could be founded.* If we do not 

 necessarily connect the name of Protopteris with botanical affinity, 

 it is a useful term to retain as pointing to a form of fern stem 

 different to that for which Lindley and Hutton's genus is retained. 



In 1865 Carruthers' published a description of a cylindrical 

 sandstone cast of Protopteris punctata from the Upper Greensand of 

 Dorsetshire ; the form of the leaf -trace bundles is clearly shown in 

 the original * of Carruthers' figure, and there can be no doubt of its 

 identity with Sternberg's Bohemian type. Unfortunately the 

 English specimen is entirely without internal structure. 



The substitution of Biohsonia for Protopteris by certain writers, 

 such as Heer, Velenovsky, and Staub, has already been referred to ; 

 the same generic name has also been used by Renault for a fossil 

 fern-stem of Cretaceous age from the Ardennes." 



1 Flor. foss. Arct. vol. vi. p. 24. •= "S. Jahib. 1836, p. 30, pi. i. 

 3 p. 449. « Geol. Mag. 1865, p. 487. ' Flor. Vorwelt, p. 77. 

 ^ Lindley and Hutton, Foss. Flora, vol. i. pi. xlii. 

 ' Loc. oit. p. 484, pi. xiii. 



* Specimen in the British Museum, registered number 39002. The plate 

 illustrating Carruthers' paper hardly does justice to this remarkably fine specimen. 

 ' Cours hot. foss. vol. iii. p. 74. 



