Slopes.—The Internal Anatomy of ‘Nilssonia orientalis \ 393 
somewhat from the rest of the species, coming closer to Taeniopteris in 
general appearance. Seward 1 says (p. 123), { Heer’s figures of Nilssonia 
orientalis , Heer, probably represent a Taeniopteris .’ And Nathorst (1 c., 
p. 29) also considers N. tenuinervis as doubtfully a Nilssonia , and that 
its affinity is more rightly indicated by the name Nilssoniopteris. 
Judged merely from the external features, this fine-veined, entire form 
of Nilssonia does seem to come nearer the genus Taeniopteris. But as that 
genus is most probably an artificial one, like many of the Palaeozoic foliage 
genera, the definition of its limits is not really important at present. 
Whether the plant I am describing belongs to the one group or the other, 
it has been described and is well known under the name Nilssonia orientalis. 
The internal anatomy of its foliage is now discovered, and has the 
features described above, which are clearly Gymnospermic rather than 
fern-like. They are, moreover, quite of the type that one might hold 
to be primitively Cycadean. 
1 Seward, A. C.: Catalogue of the Mesozoic Plants. The Wealden Flora, Pt. I. British 
Museum, London, 1894. 
DESCRIPTION OF PLATE XXVI. 
Illustrating Dr. Marie C. Stopes’s Paper on Nilssonia orientalis. 
Fig. 1. Photograph of part of the broken nodule showing a portion of the leaf of Nilssonia 
orientalis , Heer, as an impression, x 2. 
Fig. 2. Photograph of part of the leaf in the matrix, showing the petrifaction of its internal 
anatomy, ed., the edge of the leaf, r ., resin-canal and v., the vascular bundle near it. e ., the upper 
epidermis. 
Fig. 3. Enlarged photograph of the resin-canal and the bundle beside it. e., upper epidermis. 
px ., protoxylem of the bundle, r ., resin-canal, with some of its epithelial lining, ep. 
Fig. 4. Drawing of part of leaf of Nilssonia orientalis, natural size. 
