424 Notices and Extracts from the Minutes of the Geological Society. 



cation^ to arrive at natural affinities ; it being the chief failing of our system, 

 and more particularly in this interesting family, that not only it is itself arti- 

 ficial, but that for the first time, and in the science of fossil botany alone, these 

 subgenera are no longer natural, but altogether artificial divisions. Our pre- 

 sent plant approaches in habit to some of the tropical Nephrodia ; but the 

 ramification of the veins, as seen at the tips of the pinnae, distinguishes it from 

 them. These veins will not exclude it, according to his definition, from 

 Mr. Ad. Brongniart's subgenus Pecopteris ; their interlacement, however, is 

 curious, and we have named the species P. reticulata. 



The plant figured PI. XLVI. fig. 7. and XLVII. fig. 2. belongs likewise 

 apparently to the genus Filicites, if indeed the ramification of the fronds, as in- 

 dicated by the different planes in which the branches are disposed (so distinct 

 from the mere distichous frond of the ferns), does not drive it out of this family. 

 In this respect, as well as in the form of its frond, it approaches to Psilotum, 

 the species of which differ remarkably from each other in the development 

 and figure of those bifid branches, in the division of which the capsule is 

 placed. But this idea is not supported by the disposition of the vessels in the 

 ultimate segments, which more nearly resemble those of Trichomanes or Hy- 

 menophyllum. In the system of Mr. Ad. Brongniart, this plant would proba- 

 bly be a Sphenopteris, but differs both from his example of this subgenus 

 figured, and from the recent analogous genera enumerated by him as having 

 its form, in that all the divisions of the frond are bordered by a decurrent mem- 

 brane as in the genusTrichomanes, with which,as we before said, it would like- 

 wise accord in the disposition of its vessels. We have therefore thought fit 

 from the above natural characters to form a new subgenus under the name of 

 Hymenopteris, although, if it could have been so arranged, we should have 

 preferred distinguishing these fossil subgenera by a different termination, such 

 as Hymenopterites, from the recent genera Struthiopteris and others. We are 

 however unwilling, without absolute necessity, to alter what has been received, 

 and we shall therefore call our plant Hymenopteris psilotoides. 



In finishing this arrangement of the fossil flora of the Tilgate Forest, we are 

 far from wishing to desert the subject ; and should any member of the Society 

 be possessed of similar remains, for the illustration of which he maybe anxious, 

 we should feel it our duty again to enter upon these interesting but obscure 

 investigations. 



