ARKIV FÖR BOTANIK. 



BAND 17. N:o 3. 



Two new species of Mesozoic Equisetales. 



By 

 GUNNAR ERDTMAN. 



With 1 Plate. 

 Communicated Febr. 9th 1921 by C. A. M. Lindman and O. Rosenberg. 



In the palaeobotanical department of the State Museum 

 of Natural History at Stockholm there is a rich material of 

 two Mesozoic Equisetales which has not yet been described. 

 One of them, which will be described below under the name 

 of Eqiiisetites intermedins, is found in the Rhaetic of Scania 

 (Höganäs), the other is a Jurassic species, Neocalamites 

 Nathorstii sp. no v., from the Yorkshire Coast (Whitby), 



Equisetites intermedins sp. nov. 



ri. 1, figs. 1—8. 



Stems articulate, occasionally with single branches at 

 the nodes. Internodes on the impressions measuring 40—50 

 mm in length and about 8 mm in breadth; their surface 

 with distinct longitudinal furrows. Leaf-sheaths usually clos- 

 ely adpressed to the stem, about 7 mm long; teeth long, 

 lanceolate, gradually tapering to the point, their basal part 

 1 mm broad, showing no trace of a midrib. The number of 

 the segments of each sheath is the same as the number of 

 furrows on the stem, or generally 7—8 on the impression, 



Ar/iiv für botanik. Band 17. N:o 3. 1 



