68 LYCOPODIALES [CH. 



While recognising a general resemblance to the sporophylls 

 of Isoetes, certain differences are obvious : there is no ligule in 

 the fossil leaves nor are there any distinct traces of vascular 

 strands such as occur in the leaves of recent species. The 

 form of the sporangium, more elongated than in the majority 

 of recent forms, is compared by Saporta with that in a south 

 European species Isoetes setacea Spr. 



Such evidence as we have lends support to the inclusion of 

 these Portuguese fossils in the genus Isoetites, but apart from 

 the fact that we have no proof of any connexion between the 

 stems and supposed sporophylls, the resemblance of the latter 

 to those of Isoetes is, perhaps, hardly sufficient to satisfy all 

 reasonable scepticism. 



The generic name Isoetopsis was used by Saporta as more 

 appropriate ^than Isoetes for some Eocene fossils from Aix-en- 

 Provence which are too doubtful to rank as trustworthy evidence 

 of the existence of the recent genus. The species, Isoetopsis 

 suhaphylla^ is founded on impressions of small scales, 4 mm. 

 long, bearing circular bodies which are compared with sporangia 

 or spores. 



Other records of fossils referred to Isoetes need not be 

 described as they have no claim to be regarded as contributions 

 towards the past history of the genus. Heer's Miocene species 

 Isoetites Scheuzeri and /. Braunii Unger^ from Switzerland are 

 based on unsatisfactory material and are of no importance. 



Pleuromeia. 



The generic name Pleuromeia, was suggested by Corda^ for 

 a fossil from the Bunter Sandstone, the original description of 

 which was based by Mlinster* on a specimen discovered in a 

 split stone from the tower of Magdeburg Cathedral. 



The majority of the specimens have been obtained from the 

 neighbourhood of Bernburg, but a few examples are recorded 

 from Commern and other German localities: all are now included 

 under the name Pleuromeia Bternhergi. Germar, who published 



1 Saporta (88) p. 28, PL ii. pp. 16—20. 2 Heer (76) A. 



3 Corda, in Germar (52). * Munster (42) A. 



