PLANTS. 5 



Class AcROGEN^E, Ad. Brongniart, 1843. 



Pkotophyta, Endlicher. 



Cryptogames vasculares, Ad. Brongniart. 



AcROGENS, Lindley. 



Diagnosis. — '^ Steins and leaves distinguishable."^ (Lindley.) 



This group, which differs from the last in possessing a vascular system, 

 embraces the Mosses, Ferns, Lycopodiaceas, Equisetaceas, and some other allied 

 plants, all of which, with the exception of the first and last, are known to occur, or 

 to have related to forms in the Permian system. 



Sub-class FiLicALES, Lindley. 



Diagnosis. — "Vascular acrogens, with marginal or dorsal one-celled spore-cases, 

 usually surrounded by an elastic ring ; and spores of only one kind."^ (Lindley.) 



Dr. Lindley divides Ferns into three orders : OpJiioglossacecB (Adders' Tongues), 

 PolypodiacecB (ordinary Ferns), and DanaacecB (Baneworts, tropical plants). The 

 Permian species next to be described appears to belong to the second group. 



Order Polypodiace^e. 



Diagnosis. — " Spore-cases ringed, dorsal or marginal, distinct, splitting irregu- 

 larly."' (Lindley.) 



Genus Neuropteris, Ad. Brongniart. 



Diagnosis. — " Leaves bipinnate, or rarely pinnate ; leaflets usually somewhat 

 cordate at the base, neither adhering to each other, nor to the rachis, by their whole 

 base, only by the middle portion of it ; midrib vanishing at the apex ; veins oblique, 

 curved, very fine, dichotomous. Fructification .- sori lanceolate, even (covered with an 

 indusium) arising from the veins of the apex of the leaflets, and often placed in the 

 bifurcations."* (Ad. Brongniart.) 



This is an extinct genus of Ferns which abounded during the early ages of the 

 world, as remains of it are very common in the coal formation : several species also 

 occur in the Jurassic rocks ; but only one is known to belong to the Permian 

 deposits '43f Britain. 



' The Vegetable Kingdom, p. 4, 1847- 



2 Op. cit. p. 74. 



3 Op. cit. p. 78. 



* Histoire des Vegetaux Fossiles, p. 226 ; Fossil Flora, vol. i. 



