THE PLOBA. 



97 



single species of Equisetum represents the 

 Equisetaceae. 



The conifers appear to have been an unim- 

 portant element, as regards both forms and 

 ( individuals, in this flora, being represented by 

 only two genera and four forms. Of these 

 Dammara is represented by a single frag- 

 mentary scale and, of course, is of little im- 

 portance. The species of Sequoia are repre- 

 sented by several leafy branchlets. 



The only example belonging to the Cyca- 

 daceae is a beautifully preserved small trunk 

 now referred to Cycadeoidea, but unfortu- 

 nately its exact horizon is open to question. 



The monocotyledons were apparently not 

 an abundant element during the Cretaceous 

 period, and the Laramie flora is no exception, 

 though the number and variety present are 

 rather greater than might have been expected. 

 There are, for example, three forms of sedge- 

 like plants described under the name Cypera- 

 cites, and a single grass with strong, reedlike 

 stems, designated Phragmites, that must have 

 been a striking denizen of the swamps. The 

 flora contains also a fairly well-marked leaf of 

 a Smilax, and two species of palms, one of 

 which at least had leaves of large size and 

 imposing appearance. 



The dicotyledons were, of course, the most 

 abundant and diversified elements of this 

 flora. Beginning with the lower or apetalous 

 groups, we have five species of Juglans known 

 from the leaves, and two of Hicoria known 

 from the fruits. The waxberries were repre- 

 .. sented by three or four forms of Myrica, and 

 the willows by the species of Salix, some of 

 which were individually abundant. One spe- 

 cies of Populus is described, though it is neither 

 abundant nor very well marked. The oaks 

 are represented by four forms of Quercus, one 

 of which (Q. praeangustiloba) was a deeply 

 lobed leaf of modern appearance. 



The large, mainly tropical family Moraceae 

 was apparently an abundant and diversified 

 element, embracing two species of Artocarpus 

 or breadfruit that possessed very strongly 

 marked leaves and 21 species of Ficus. The 

 figs were not only more abundant in species 

 but also in individuals, as there is hardly a 

 collection that does not contain from one to 

 several species. A number of the species have 

 leaves of large size. 



Aristolochia was represented by a single 

 species with leaves of much the same shape as 

 two well-known European forms. In both 

 form and nervation it approaches an American 

 species (A. sipho). To the Nymphaeaceae 

 is referred a fine species of Nelumbo with 

 large peltate leaves. 



The Magnoliaceae, although represented by 

 two species of Magnolia, were neither abundant 

 nor of especially striking aspect, as the small 

 leaves indicate. 



The Lauraceae embrace three genera and 

 five species — Laurus with two, Malapoenna 

 with one, and Cinnamomam with two. Oinna- 

 mdmum affine was abundant and widely dis- 

 tributed. ' 



The Platanaceae were very . poorly repre- 

 sented, there being only one small-leaved form 

 and a doubtful fragment not specifically 

 named. The named species (Platanus plata- 

 noides) .was first referred to Viburnum, and its 

 reference to Platanus is not positively authen- 

 ticated. 



The Leguminosae are supposed to be repre- 

 sented by three forms of Leguminosites, one of 

 Mimosites, and a very doubtful Oercis. The 

 two forms of Celastrinites and one of Negundo 

 show little of special biologic interest. There 

 are three forms of Oornus, two each of Anond 

 and Pistacia] four of Dombeyopsis, and one 

 each of Fraxinus, ApocynopJiyllum, Hedera, 

 and Ilex. Of the more or less indefinite 

 Carpites there are four, and of Phyllites about 

 seven forms. 



ECOLOGIC RELATIONS OF THE FLORA. 



After having briefly reviewed the Laramie 

 flora, we are in position to draw at least tenta- 

 tive conclusions regarding the ecologic condi- 

 tions which appear ' to have existed during 

 Laramie time. As I have had occasion to 

 remark in another similar connection: 



In estimating the value of individual organisms in' an 

 inquiry of this kind, dependence must of course be placed 

 on our knowledge of present-day requirements, and in this 

 there is always the possibility of error from two sources, 

 namely, (1) the organism may not have been correctly 

 placed biologically, and (2) the requirements in past 

 geologic time may not have been the same as those which 

 now dominate the life activities of its supposed analogue. 

 However, when all of the elements of a flora appear with 

 apparent unanimity to point in the same direction, the 

 liability to serious error is minimized if not eliminated. 



