44 Later Extinct Floras cf North America, 



of Miocene Btrata have furnished Bpecimens of sonic one of the 

 various phases'of what is regarded by Prof. Heer as a single 

 species, lnit which lias been described under the three names 

 of 0'. 1:' ■,■■'' j, G. Ungerif and G. Oeningensis. 



"What I have regarded a> probably but a variety of this same 

 plant was collected by the U. S. Exploring Expedition under 

 Capt. Wilkes, at Birch Bay, near the mouth ofFrazer'6 River. 

 B. C. by (reo. Gibbs, Esq., Geologist to the X. W. Boundary 

 Commission (see Journal of l»oston Nat. Hist. Sue, vol. vii. 

 No. 4), and is represented by numerous specimens in the col- 

 lection of fossil plants made by Dr. Bayden on the Yellowstone 

 and Upper Missouri. 



In this country, as in Europe, the foliage of Glyptostrdbus 

 exhibits two forms wherever the plant is found; the short ap- 

 pressed, and the longer divergent leaves. In addition to this. 

 the specimen:- from the X. W. coast have a common character 

 by which they may he distinguished at once from those col- 

 lected by Dr. Eayden. The Western plant is more slender, 

 the appressed leaves sharper and more delicate, the divergent 

 leaves much longer, corresponding more nearly to the Euro- 

 pean form described as G- Uhgeri, while those from the l'p- 

 per Missouri resemble more the variety known as G. Eurqpa ue. 



The cones, however, found with tin' Missouri specimens are 



more like those of G. Ungerithan a. Ewropams; the dorsum of 



the scale being marked by short, radiating carina', as in (i. 



TJngeri, the margin being waved, hut not regularly scalloped, 

 as in G. Ewopa US. 



From the extreme West we have a- yel no cones which can 

 l,e certainly referred to this plant, so that the most important 

 element in the comparison is wanting, hut it would seem that 

 hen-, a- in Europe, the different phases of the plants belonging 

 to the L r eiius Glyptost/robus are so linked together, that they 

 should he regarded a- forming hut a Bingle Bpecies. At Least 

 we has. not vet obtained sufficient material, to justify us in 

 attempting to define the limits of other species. 



