96 



LARAMIE FLORA OF THE DENVER BASIN. 



Cercis eocenica Lesquereux. 



Celastrinites alatus Knowlton, n. sp. 



Celastrinites eriensis Knowlton, n. sp. 



Celastrinites cowanensis Knowlton, n. sp. 



Negundo brittoni Knowlton, n. sp. 



Pistacia eriensis Knowlton, n. sp. 



Pistacia hollicki Knowlton, n. sp. 



Ilex laramiensis Knowlton, n. sp. 



Ceanothus eriensis Knowlton, n. sp. 



Ceanothus ovatifolius Knowlton, n. sp. 



Rhamnus goldianus? Lesquereux. 



Rhamnus salicifolius Lesquereux. 



Rhamnus minutus Knowlton, n. sp. 



Rhamnus marshallensis Knowlton, n. sp. 



Rhamnus belmontensis Knowlton and Cockerell. 



Rhamnus brittoni Knowlton, n. sp. 



Rhamnus? pealei Knowlton, n. sp. 



Rhamnus sp. 



?Paliurus zizyphoides Lesquereux. 



Zizyphus coloradensis Knowlton, n. sp. 



Zizyphus hendersoni Knowlton, n. sp. 



Zizyphus corrugatus Knowlton, n. sp. 



Zizyphus minutus Knowlton, n. sp. 

 Apeibopsis? laramiensis Knowlton, n. sp. 



Cornus suborbifera Lesquereux. 



Cornus praeimpressa Knowlton, n. sp. 



Cornus sp. 



Hedera lucens KnowltQn, n. sp. 



Diospyros berryana Knowlton, n. sp. 



Fraxinus? princetoniana Knowlton, n. sp. 



Apocynophyllum taenifolium Knowlton, n. sp. 



Dombeyopsis obtusa Lesquereux. 



Dombeyopsis trivialis Lesquereux. 



Dombeyopsis? sinuata Knowlton, n. sp. 



Dombeyopsis ovata Knowlton, n. sp. 



Carpites lakesii Knowlton, n. sp. 



Carpites lesquereuxiana Knowlton, n. sp. 



Carpites rhomboidalis Lesquereux. 



Phyllites leydenianus Knowlton, n.. sp. 



Phyllites marshallensis Knowlton, n. sp. 



Phyllites trinervis Knowlton, n. sp. 



Phyllites dombeyopsoides Knowlton, n. sp. 



Phyllites sp. 



Phyllites sp. 



Phyllites sp. 



Palaeoaster? similis Knowlton, n. sp. 



BIOLOGIC RELATIONS OF THE FLORA. 



The Laramie flora as herein set forth is not 

 an especially rich one as regards specific forms, 

 types of vegetation represented, or individual 

 specimens. Most of the plants have been 

 found in more or less direct connection with 

 the coal. A few of them were found in a 

 fine-grained sandstone or shale, and so far as 

 they are retained in this matrix they are 

 fairly well preserved and admit of satisfactory 

 study. In some places the sandstone matrix, 

 although fine grained, is so hard as to render 

 it difficult , to procure perfect specimens, 



though in perhaps the most fossiliferous locali- 

 ties the matrix is a rather coarse-grained, 

 soft sandstone that crushes or breaks so 

 readily that good material is the exception. 

 As much of the rock disintegrates rapidly on 

 exposure, it is almost impossible to procure 

 identifiable material unless it happens to be 

 collected very soon after it is brought out. 

 All these conditions help to explain why so 

 many of the plants appear fragmentary. 



The great group of the algae is represented 

 by a single more or less doubtful specimen 

 that has been referred to the genus Delesseria. 

 This is, of course, a very inadequate expres- 

 sion of the algal life that must have existed 

 in the abundant coal swamps and streams of 

 the time. None of the other groups of lower 

 plants below the ferns — that is, fungi, simple 

 algae, mosses, hepatics, etc. — are repre- 

 sented in the collections. 



The ferns, although not very abundant as 

 individuals, are diversified in type, being 

 represented by 8 genera and 14 forms. One 

 of the most interesting, but unfortunately 

 also one of the most fragmentary, is repre- 

 sented by the form for which the genus PJian- 

 erophlelites is created. Its nervation is very 

 similar to that of the living PhaneropMebia 

 ndbilis (Aspidium nobile Chamisso and Schlech- 

 tendahl) and PhaneropMebia juglandifolia (Will 7 

 denow) J. Smith, both from Mexico. What is 

 believed to be the fruiting stage of an Onoclea 

 is represented by Onoclea fecunda, a form 

 originally described as Caulinites. The sterile 

 leaves of this form have not been detected. 

 The largest representation is found in forms 

 referred to Dryopteris, of which there are five 

 species. Perhaps the finest of these is the form 

 here named^ Dryopteris georgei, which must 

 have been of rather imposing size and appear- 

 ance, as the pinnae must have been 15 or 20 

 centimeters long and 6 to 8 centimeters wide. 

 A small, rather coriaceous form is described as 

 Dryopteris? carbqnensis. The only form re- 

 ferred to Asplenium is fragmentary, but to 

 judge from the portion found it was of striking 

 appearance; it appears to be rather closely allied 

 to a species in the Vermejo formation of the 

 Raton Mesa region. Pteris is represented by 

 two forms, neither of which, however, is very 

 well preserved. The Schizaeaceae are repre- 

 sented by a single, rather doubtful species of 

 Lygodium and three forms of Anemia. A 



