ERDTMAN, TWO NEW SPECIES OF MESOZOIC EQUISETALES. 5 



cylinder) than of leaves or leaf-teeth. The proportion between 

 the number of the lists and the number of the leaves is in 

 Neocalamites Carrerei and N. hoerensis about 2,5 : 1, in the 

 geologically younger N. Natliorstii about 1,5 : 1. For an exact 

 ascertainment of this proportion it is necessary to be in 

 possession of older, full-grown stems, as at the ends of the 

 branches and the stems the number of furrows is mostly the 

 same as the number of leaves or leaf -teeth. In the case of 

 N. Nathorstii the scars left after the fall of the leaves do 

 not facilitate the computation of the above-mentioned pro- 

 portion, since they are not preserved on most of the spe- 

 cimens. It has been easier to find the proportion between 

 the number of the preserved leaves and that of the furrows. 

 The great distance between the leaf-bearing nodes shows that 

 they cannot possibly have been young stem-fragments. 



Finally it may be mentioned that a couple of specimens 

 contain fragments which might be regarded as tubers of Neo- 

 calamites. It has not been possible to prove any connection 

 between these fragments and other rhizome-parts; but the 

 shape of these objects and their association with other 

 remains of the plant are in favour of this interpretation. 

 Fig. 12 shows a little tuber, fig. 13a greater (length 30 mm, 

 breadth 17 mm); a third tuber is 20 mm long and 16 mm 

 broad. 



Before I finish this paper, I would express my best 

 thanks to Professor Th. G. Halle for suggestions and help 

 in various forms. 



The Palaeobotanical Department of the Natural History 

 Museum of Stockholm, November 1920. 



Literature. 



Berry, E. VV., American Triassic Neocalamites. — Botanical Gazette, 1912. 

 A Restoration of Neocalamites. — American Journal of Science, 



Vol. XLV, June 1918. 

 Fontaine, F. M , Contribution to the knowledge of the older Mesozoic 



flora of Virginia. — Monograph U. S. Geol. Surv., (i, 1883. 

 Halle, T. G , Zur Kenntnis der mesozoischen Equisetales Schwedens. — 



Kungl. Svensi<a Vet. Akad. Hand!., Bd 43, n:o 1, 1908. 

 Möller, H. and Halle, T. G., Tho fossil flora of the coal bearing deposits 



of southeastern Scania. — Arkiv för Botanik, Bd 13, n:o 7, 1913. 



