[pENHALLOW] CRETACEOUS AND TERTIARY PLANTS OF CANADA 49 
the diagnosis for L. fischeri, but in the latter there are about ten 
nerves on each side of the midrib, while in our specimen the nerves 
never exceed seven pairs, and there are frequently not more than four. 
It is therefore provisionally referred to L. fischeri. 
EQUISETUM ARCTICUM, Heer. 
Heer, Miocene Flora and Fauna of Spitzbergen, 1870, 31, Pl. I., 1-15; II., 2 & 3b. 
Dawson, Trans. R. Soc. Can., IV. (1886), iv., 22, Pl. I., 2. 
Miocene of Spitzbergen; Eocene of Red Deer River, Canada. 
The original description of this species appears in Heer’s Miocene 
Flora of Spitzbergen, where also several excellent figures of the plant 
are given, showing the stem in longitudinal and transverse aspects, 
together with numerous tubers. The plants are shown to closely 
resemble the existing species of E. limosum, and they are found in great 
abundance at King’s Bay. 
In the material from Red Deer River, there are no complete stems. 
These structures are represented only in end view, and show nodal 
sections from which roots and tubers radiate. The tubers, when 
perfect, are upwards of 7 mm. wide and 2 cm. long. ‘They are borne 
upon short stalks and are somewhat broadly elub-shaped, with an abrupt 
or almost truncate termination. The surface is strongly rugose. The 
very close resemblance which these specimens bear to E. arcticum, leaves 
no room for doubt that they may be referred to that species.  Les- 
quereux describes an Equisetum from the Tertiary of Green River 
Station, Wyoming, under the name of E. wyomingense which it is 
very difficult to separate from E. arcticum, the only real difference 
appearing in the length of the internodes. 
Sir William Dawson observed two species of Equisetum in the 
Upper Laramie of Porcupine Creek and of Great Valley* in lat. 49, 
long. 105. The specimen from Porcupine Creek is neither figured 
nor described, but it is spoken of as having a diameter of one quarter 
of an inch, and its close resemblance to E. arcticum of Heer, and to 
E. wyomingense of Lesquereux is noted, but identity could not 
be established. The specimen from Great Valley is not described, 
but it is figured. The figure shows a short fragment of stem with 
tubers. The plant was described in the Report on the 49th Parallel 

+ Trans. R. Soc. Can., IV. (1886), iv., 22. 
