134 



LARAMIE FLORA OF THE DENVER BASIN. 



This species, of which a very good figure is 

 given, appears to be represented only by this 

 example. It lacks the basal portion and most 

 of the margin on one side, but as nearly as can 

 be made out it is about 10 or 12 centimeters in 

 length and about 6 centimeters in width at the 

 broadest point, which seems to be a little above 

 the middle. The nervation is very distinct 

 and regular, as described above. 



This species is undoubtedly most closely re- 

 lated to Ficus planicostata Lesquereux, 81 from 

 which it differs in its apparently wedge-shaped 

 base, more pointed apex, and more erect, rela- 

 tively slenderer nervation, for it is in a way 

 intermediate between this and Lesquereux's 

 variety clintoni, but it appears sufficiently dis- 

 tinct from F. planicostata by the characters 

 mentioned, and it is clearly distinct from the 

 variety clintoni. Additional material may give 

 evidence of variation in the direction of the 

 typical form, but until that is forthcoming this 

 may stand as a distinct though obviously 

 closely related variety. 



Occurrence : Laramie formation, Coal Creek, 

 Boulder County, Colo. 



Ficus impressa Knowlton, it. sp. 



Plate VII, figures '1-3; Plate XVI, figure 3. 



Ficus impressa Knowlton [nomen nudum], U. S. Geol. 

 Survey Bull. 696, p. 278, 1919. 



Leaves of thick texture, uniform size, and 

 ovate or elliptical outline, rounded and trun- 

 cate or very obtusely wedge-shaped at the base, 

 obtusely pointed at the apex; margin entire; 

 nervation deeply impressed, three-ribbed from 

 the base of the blade, the midrib slightly the 

 strongest, with about three pairs of strong 

 camptodrome secondaries above the middle; 

 lateral ribs at an angle of 50° or 60°, each with 

 five to seven secondary branches on the out- 

 side, these camptodrome and arching just 

 inside the margin; nervilles y er y numerous, 

 strong, often broken. 



This species is represented by a considerable 

 number of examples, one of which is nearly 

 perfect. They are about 7 centimeters in 

 length and vary in width from 3.5 to 6 centi- 

 meters. 



This species is, also the type of Ficus plani- 

 costata Lesquereux, from which it differs in, 



»i Lesquereux, Leo, The Tertiary flora: U. S. Geol. Survey Terr. 

 Rept., vol. 7, pi. 31, 1878. 



being narrower, more elliptical, and less trun- 

 cate at the base. The lateral ribs are at a 

 slightly more acute angle, and both these and 

 the secondary branches are less regular; the 

 nervilles are the same in both. 



Occurrence: Laramie formation, Marshall, 

 Colo., collected by Arthur Lakes, 1890. 



Ficus coloradensis Cockerell. 



Plate XXII, figure 1. 



Ficus coloradensis Cockerell, Torreya, vol. 10, p. 223, 1910. 

 Ficus irregularis (Lesquereux) Lesquereux, U. S. Geol. 



and Geog. Survey Terr. Ann. Rept. for 1874, p. 



304, 1876; idem, Bull., vol. 1, p. 368, 1876; Tertiary 



flora: U. S. Geol. Survey Terr. Rept., vol. 7, p. 



196, pi. 34, figs. 4-7, 1878; Harvard Coll. Mus. Comp. 



Zoology Bull., vol. 16, p. 50, 1888. [Homonym, 



Miquel, 1867.] 

 Ward, U. S. Geol. Survey Sixth Ann. Rept., p. 552, 



pi. 44, fig. 4, 1886 [not fig. 5, which =Rhamnus 



goldianus]; U. S. Geol. Survey Bull. 37, p. 38 



pi. 20, fig. 4, 1887 [not fig. 5, which.=Rhamnus 



goldianus]. 

 Knowlton,-U. S. Geol. Survey Bull. 163, p. 51, 1900. 

 Ulmusf irregularis Lesquereux, U. S. Geol. and Geog. 



Survey Terr. Ann. Rept. for 1872, p. 378, 1873. 



A good deal of confusion seems to be current 

 regarding the distribution of this species. It 

 was originally described under the name 

 Ulmusf irregularis from specimens found 

 in the Denver beds at Golden, Colo., and sub- 

 sequently was reported by Lesquereux from 

 Point of Bocks, Black Buttes, and Carbon, 

 Wyo. The type specimens figured by Les- 

 quereux in the "Tertiary flora" (PI. XXXIV, 

 figs. 4-7) are preserved in the United States 

 National Museum and are before me. The 

 originals of Lesquereux's figures 5, 6, and 7 

 (Museum Nos. 296, 297, 831) .are all in the 

 andesitic material characteristic of the Denver 

 beds, and additional examples are to be found 

 in subsequent collections from this area. The 

 original of his figure 4 (Museum No. 295) is 

 recorded as coming from Carbon, Wyo., but 

 later collections from this locality do not seem 

 to contain it. 



The material upon which Lesquereux based 

 his statement of the abundant presence of 

 F. irregularis at Black Buttes is not to be 

 found in the Museum collections, and as this 

 species has not been found there by any of the 

 subsequent collectors, Lequereux's statement 

 may be set down as extremely doubtful and 

 not entitled to any consideration. 



