THE CARBONIFEROUS FLORA. 



173 



distinctive characters are leaflets narrowed at the base, often lobed, 

 and with nervures dividing in a pinnate manner from the base. 



7. Phyllopteris, Brongniart. — These are pinnate, with long lan- 

 ceolate pinnules, having a strong and well-defined midrib, and 

 nerves proceeding from it very obliquely, and dividing as they pro- 

 ceed toward the margin. The ferns of this genus are for the most 

 part found in formations more recent than the Carboniferous ; but I 

 have referred to it, with some doubt, one of our species. 



8. Alethopteris, Brongniart. — This genus includes many of the 

 most common coal-formation ferns, especially the ubiquitous A. lon- 

 chitica, which seems to have been the common brake of the coal- 

 formation, corresponding to Pteris aquilina in modern Europe and 

 America. These are brake-like ferns, pinnate, with leaflets often 

 long and narrow, decurrent on the petiole, adherent by their whole 

 base, and united at base to each other. The midrib is continuous to 

 the point, and the nervures run off from it nearly at right angles. 

 In some of these ferns the fructification is known to have been mar- 

 ginal, as in Pteris. 



9. Pecopteris, Brongniart. — This genus is intermediate between 

 the last and Neuropteris. The leaflets are attached by the whole 

 base, but not usually attached to each other ; the midrib, though 

 slender, attains to the summit ; the nervures are given off less ob- 

 liquely than in Neuropteris. This genus includes a large number of 

 our most common fossil ferns. 



10. Beinertia, Goeppert. — A genus established by Goeppert for a 

 curious Pecopteris-like fern, with flexuous branching oblique ner- 

 vures becoming parallel to the edge of the frond. 



11. Hymenophyllites, Goeppert. — These are ferns similar to 

 Sphenopteris, but divided at the margin into one-nerved lobes, in the 

 manner of the modern genus Hymenophyllum. 



12. Palceopteris, Geinitz. — This is a genus formed to include cer- 

 tain trunks of tree-ferns with oval transverse scars of leaves. 



13. Caulopteris, Lindley and Hutton. — Is another genus of fossil 

 trunks of tree-ferns, but with elongate scars of leaves. 



14. Psaronius, Cotta. — Includes other trunks of tree-ferns with 

 alternate scars or thick scales, and ordinarily with many aerial roots 

 grouped round them, as in some modern tree-ferns. 



15. Megaphyton, Artis. — Includes trunks of tree-ferns which 

 bore their fronds, which were of great size, in two rows, one on each 

 side of the stem. These were very peculiar trees, less like modern 

 ferns than any of the others. My reasons for regarding them as 

 ferns are stated in the following extract from a recent paper : 



