330 Reviews — Dr. D. Stiir — Fossil Ferns of the Coal- Measures. 



be placed in Scolecopteris, Zenker. The sporangium of Grand' Ear y a, 

 Zeiller (not Stur), has a very prominent and curiously formed 

 annulus, but in the ferns placed by Stur in his Grand' Eur y a, the 

 sporangia are exannulate. 



Oligocarpia, Goppert. — This genus is included in the Marattiacece 

 by Dr. Stur, but the presence of an annulus on the sporangia of 

 Oligocarpia excludes it from this order. The annulus is clearly 

 shown on the enlarged drawings of the groups of sporangia given 

 by him (figs. 14 and 15, p. 55). The single sporangium on fig. 15 

 exhibits the point by which it has been attached, turned uppermost. 

 Dr. Stur has evidently mistaken the base for the apex of the 

 sporangium. Zeiller thinks that the affinities of the Oligocarpia are 

 with Gleichinia. 



DiscoPTERis, Stur. — It is probable that in this genus, as consti- 

 tuted by Stur, there are included two distinct types of fructification. 

 Discopteris Schumanni, Stur, seems identical with the genus 3Iyrio- 

 theca, Zeiller.^ 



The other fern, Discopteris Karicinensis, Stur, might be regarded 

 as the type of his Discopteris, which would thus require to be 

 emended. It is impossible, from the meagre evidence before us, to 

 indicate the affinities of this genus. 



Saccopteris, Stur. — An example of the errors which are sure to 

 arise from including barren species in genera founded on characters 

 derived from the fruit is well illustrated here, for Stur includes in 

 his Saccopteris, Sphen. coralloides, Gutbier, whose fruit has previously 

 been described by Zeiller, but the paper in which the description 

 occurs seems to have been unknown to Stur.^ 



In Grand' JEurya coralloides, Gutbier sp., the annulus is very 

 prominent, and placed in five or six vertical lines, whereas in 

 Saccopteris it is apical and very rudimentary. These differences 

 preclude these two ferns from being placed in the same genus. The 

 jDresence of an annulus (though rudimentary in Saccopteris Essinghi, 

 Andr. sp.) also excludes it from the Marattiacece. 



Scolecopteris, Zenker. — Included here are a great many Pecop- 

 teroids, but there is scarcely enough evidence amassed for bringing 

 together the various species Stur places in this genus. The fruit of 

 Pecopteris (Scolecopteris) polymorpha, Brongt., placed alongside of 

 Pecopteris (Scolecopteris) arhorescens, Schloth. sp., scarcely seems 

 admissible. More intimate knowledge of the fruit. of the genus 

 Pecopteris, Brongt., must be obtained before any arrangement of this 

 group can be formed on a satisfactory basis. 



Eenaultia, Stur. — The plants placed in this genus are quite 

 distinct from those for which Zeiller proposed the name, so much 

 so, that one can only again conclude that Stur was ignorant of 

 Zeiller's genus Benaultia? The ferns included in it by Stur have 

 an apical annulus, whereas Zeiller's plants have exannulate sporangia. 

 The presence of an annulus in Pecop. intermedia, Eenault, the type 

 of Stur's genus, excludes it from the Marattiacece. 



1 loc. cit. p. 186, pi. ix. f. 18-20. » fo^. cit. p. 203. 



» loc. ctt. p. 185, pi. ix. f. 16-17. 



