PROTOPTERIS. vi! 
bearing strata of Bohemia, from which Sternberg’s specimen was 
obtained, were of Cenomanian age, and this led Heer 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 ‘ Fossilen Farrnkriuter.” * 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 Cyatheacee; the original name, P. punctata, being 
replaced by that of P. Sternbergii. The name Protopterts 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 Dicksonia 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. * N. Jahrb. 1836, p. 30, pl. i. 
3 p. 449. 4 Geol. Mag. 1865, p. 487. 5 Flor. Vorwelt, p. 77. 
§ Lindley and Hutton, Foss. Flora, vol. i. pl. xlii. 
7 Loc. cit. p. 484, pl. xiii. 
8 Specimen in the British Museum, registered number 39002. The plate 
illustrating Carruthers’ paper hardly does justice to this remarkably fine specimen. 
® Cours bot. foss. vol. iii. p. 74. 
