160 



LARAMIE FLORA OF THE DEX\'ER BASIN. 



only two additional examples of Cornus im- 

 pressa have been collected. These are a 

 broken individual from the andesitic beds at 

 Golden, Colo., and the leaf from the ravine 

 opposite St. Luke's Hospital in Denver, which 

 was described by Ward '^ as Cornris erninonsii. 

 The other leaf described and figured by 

 Ward^' under the name Cornvs emmonsii came 

 from beds known to be of Montana age at 

 Point of Rocks, Wyo. In my "Flora of the 

 Montana formation"^* this specimen was also 

 referred to Cornus impressa on the basis of the 

 figure of it given by Ward, but the specimen 

 itself was not then available. This figure will 

 be seen to agree very closely with that of 

 Cornus iinpressa, though much of the essential 

 part of it has been entirely misinterpreted and 

 incorrectly dra^\^l. The margin throughout 

 and the distal terminations of the secondaries 

 are exceedingly obscure. Several of the sec- 

 ondaries seem to enter the margin, but in one 

 place it is possible to demonstrate with con- 

 siderable certainty that they are camptodrome 

 and arch just within the margin; hence it is 

 probable that all do this. But the apex is 

 entirely wrong in the figure. The point at 

 which it is there made to curve inward is 

 clearly a break, and it was undoubtedly pro- 

 longed for a distance of probably 3 or 4 centi- 

 meters beyond the point where it is now made 

 to terminate. This is showni by the undimin- 

 ished thickness of the midrib at the broken 

 upper margin of the blade, as well as by the 

 upper pairs of secondaries, which do not arch 

 but clearly pass beyond the broken margin. 

 This leaf was undoubtedly ovate-acuminate, 

 instead of elliptical-oblong, and is in all proba- 

 bility a small leaf of what has with some hesi- 

 tation been called Cornus studeri. In any 

 event it can not possil)ly be the same as Cornus 

 impressa, and I doubt whether it should be 

 given specific rank. 



Among the specimens from tlie cut on the 

 Moffat railroad (Denver & Salt Lake) near the 

 Leyden mine is a piece of matrix bearing a 

 small leaf of this species and a broken leaf of 

 Rhamnus salicifolius. It is only about 5 cen- 

 timeters long and 2.5 centimeters wide but 

 does not otherwise differ essentially from the 

 larger example figured. 



M U. S. Geol. Survey Sixth Ann. Kept., p. 653, pi. 48, flg. 2, 1886; 

 U. S. Geol. Survey Bull. 37, p. 55, pi. 2fi. fle. 2. 1887 

 " Op. clt. (Sixth Ann. Rept.), pi. 48, flg. 3. 

 " U. S. Oeol. Survey Bull. 163, p. 68, 1900. 



Occurrence: Laramie formation, Cowan sta- 

 tion, 10 miles south of Denver, Colo., collected 

 by F. H. Knowlton; cut on Moffat railroad 

 (Denver & Salt Lake) , collected by A. C. Peale, 



1908. 



Cornus sp. 



Plate XIV, figure 4. 



Leaf of firm texture, elliptical or perhaps 

 elliptical-obovate; margin entire; nervation pin- 

 nate, the midrib strong, straight; secondaries 

 about six or seven pairs, at an angle of about 

 45°, alternate below, subopposite above, camp- 

 todrome, arching just inside the border, the 

 upper ones much curved inward and probably 

 reaching the midrib. 



The specimen here figured is the only one 

 obtained, and this is fragmentary, lacking all 

 of the base and one side and the extreme tip. 

 It was about 8 centimeters long and a little 

 over 5 centimeters wide. It is very obtuse and 

 rounded above and was probably abruptly 

 rounded below. 



This form is of the same type as Cornus 

 suborhifera Lesquereux and Cornus praeim- 

 pressa Knowlton, just described, but differs in 

 its fewer secondaries at a more acute angle. 



Occurrence: Laramie formation. Cowan sta- 

 tion, 10 miles south of Denver, Colo., col- 

 lected by F. H. Knowlton. 



Family ARALIACEAE. 

 Hedera lucens Knowlton, n. sp. 



Plate IX, figure 1. 



Hedera lucens Knowlton [nomen nudum], U. S. Geol. 

 Survey Bull. 696, p. 315, 1919. 



Leaves small, thick, evidenth' smooth and 

 polished on the upper surface, deltoid-ovate, 

 truncate and square-cut across the base, ob- 

 tusely acuminate at the apex; margin entire; 

 petiole thin, evidently short; midrib thin, 

 straight; secondaries about five or six pairs, 

 very thin and delicate, camptodrome: finer 

 nervation obsolete. 



This fine little species is represented by two 

 leaves preserved side by side on the same piece 

 of matrix. One is absolutely jierfcct; the 

 other is somewhat fragmentary but shows well 

 the nervation. The perfect example is 3 cen- 

 timeters long and 2.3 centimeters wide, and, 

 so far as can be made out, the other was of 

 similar dimensions. 



Occurrence: Laramie formation, Erie, Colo. 



