URTICACEAE. 



Nuts belonging to the Urticaceae are not uncommon, and no fewer than five 

 species are probably represented. Three of these appear to belong to Urtica, the other 

 two suggest another genus with nuts resembling Girardinia. In addition we figure two 

 other small nuts which may belong to the same family. 



The nuts of Urticaceae unfortunately are not easy to determine, either generically 

 or specifically, and we are obliged to leave the position of the Reuverian fossils still 

 uncertain. All that can be done is to describe the forms as far as the available material 

 will allow, without giving them specific names. It may be remarked in passing that 

 the species belonging to this family have been photographed upside down, so as to 

 show clearly the attachment. This has been done in other families also, where the base 

 exhibits critical characters, and must be lighted so as to show them. 



URTICA URENS Linn.? 



PI. VI, fig. 2. 



Nut small, closely resembling that of U. mens in shape, surface sculpture, and 

 attachment, but much smaller. 



Length 1.2 mm., breadth 0.9 mm. Swalmen. 



In size this corresponds with Teglian and Cromerian specimens. 



URTICA DIOICA Linn.? 

 PI. VI, fig. 3. 



Nut minute, closely resembling that of U. dioica but much smaller. 



Length 1.0 mm., breadth 0.75 mm. Reuver. 



In size this corresponds with Teglian and Cromerian specimens. The small size 

 of these two species may therefore be due merely to shrinkage during carbonisation ; 

 the other differences are so slight as not to be of specific value. Both species are very 

 rare in the Reuverian. 



URTICA Sp. 3. 

 PI. VI, fig. 4. 



Nut broadly ovate acute compressed widely margined, sides covered with retic* 

 ulate veins. 



Length 1.4 mm., breadth 1.1 mm. Swalmen, Reuver. 



In outline this nut much resembles U. urens, but it is slightly smaller, more 

 acute, and more conspicuously and widely margined. Urtica mens shows traces of 

 similar reticulation ; but the veins are much less conspicuous. This species is rare, only 

 2 nuts having been found at Swalmen and 2 at Reuver. 



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