DESCRIPTIONS OF SPECIES. 137 



gins entire or serrate, nervation strong, pinnate, midrib flexuous, lateral 

 nerves arched upward, branching at summit." 



Collected by Dr. F. V. Hayden. 



I have been able to detect no relationship between these leaves and 

 those of any living plants, and publish the figures and description given in 

 hopes that others may be more successful. They have the general aspect 

 of those of a Lauraceous tree, but I suspect they are related to those now 

 described under the names of P. cameosus and P. cupanioides. 



Formation and locality: Tertiary (Fort Union group). Fort Union, 

 Dakota. 



NOKDENSKIOLDIA BOEEALIS Heer. 



PI. LXVUI, figs. 4-6. 

 Fl. Foss. Aret., Vol. II, Abth. Ill (1870), p. 65, PI. VII, figs. 1-13. 



Professor Heer describes a capsulary dry fruit which he has called by 

 the name given above. It occurs in groups, is spheroidal, dehiscent, with 

 ten to twelve carpels of which the section is wedge-shaped, the smaller 

 angle turned inward to a central vertical axis. Professor Heer compares 

 this fruit with that of Gistus ladaniferus, to which it has a g-eneral resem- 

 blance. It was collected at Cape Staratschin (Spitzbergen) with Nymplma 

 arctica and fragments of Phragmites and of Sparganium ; also at Atanekerd- 

 luck (Greenland). From its associates in Spitzbergen it would seem to be 

 the fruit of an aquatic plant. In the Green River Shales Dr. White has 

 collected numerous specimens which are apparently identical with those 

 described by Heer. Some of these are grouped in such a way that it is 

 evident that the fruit was compound; that is, a number were aggregated 

 in a spike or crowded panicle, while the scattered capsules represented in 

 our figs. 5 and 6 are distinctly pedunculated and apparently terminated in 

 a rostrum, the prolongation of a central axis. 



After a somewhat extended comparison with the fruits of various plants, 

 I am compelled to question the conclusion that these have any botanical 

 affinity with Cistus, and it seems to me the plant here represented was more 

 likely allied to Allisma. By the examination of the fruit of our Alisma 

 plantago it will be seen to be a rounded head, flattened or excavated above, 

 consisting of a number of triangular capsules combined precisely as in the 

 Nordenskioldia. This resemblance, taken in connection with the apparent 



