132 



LARAMIE FLORA OF THE DENVER BASIN. 



are differences, but the leaf from Bridge Creek 

 should probabh' be referred to another species. 



A single broken leaf from Green Mountain, 

 Golden, Colo., I am imable to distinguish , from 

 this species, but as it is only the basal portion 

 I may be in error. 



In the material from the vicinity of the 

 Douglas mine, Sedalia, Colo., I find a single 

 small leaf that is referred with some hesitation 

 to this -species. It is smaller than the ordinary 

 leaves of F. planicostata, being only about 4 

 centimeters in length and 3 centimeters in 

 width, and is obtusely wedge-shaped instead 

 of rounded or subcordate at the base, and, 

 further, the lateral ribs, which arise at the very 

 base of the blade, have a greater number of 

 secondary branches than is usual in this species. 

 However, the thick texture of the leaf, the 

 palmately three-ribbed nervation, and the 

 strong ncrvilles are all suggestive of F. plani- 

 costata. If numerous other leaves agreeing 

 with this one are found, it should be removed, 

 either as a new variety or possibly as a full 

 species. 



The recently collected material from the 

 Denver beds also contains at least one example 

 that apparently must be referred to F. plani- 

 costata. It is about the size of the largest 

 example figured by Lesquereux ** and has the 

 short petiole preserved. It is slightly less 

 rounded at the base than is usual with this 

 species, but otherwise I am miable to see any 

 mark of difference. 



The material from Rock Springs also em- 

 braces a single fairly well preserved leaf that, 

 although not quite normal, must be referred 

 to this species. It is a rather small leaf with a 

 long petiole and is slightly less full and rounded 

 at the base than is usual in F. planicostata, but 

 in shape (other than as just noted), as well as 

 in the primary and secondary nervation, it is 

 indistinguishable. 



Occurrence: Laramie formation. Coal Creek, 

 Boulder County, Colo.; Hoyt coal mine, 1 mile 

 south of Golden, Colo. Post-Laramie (in my 

 opinion). Black Buttes, Wj-o. (types). Den- 

 ver formation, Golden and Sedalia, Colo. Wil- 

 cox formation, Shreveport, La. Mesaverde 

 formation, Rock Springs, Wyo. 



"Op. cit. (Tertiary flora), pi. 31, fig. 1. 



Ficus cockerelli Enowlton. 



Plate XII, figure 2; Plate XXIII, figures 1, 2. 



Finis cocherelli Knowlton, U. S. Geol Survey Bull. 696, 

 p. 273, 1919. 



Ficus lalifolia (Lesquereux) Knowlton, U. S. Geol. Siu-vey 

 Bull. 152, p. 102. 1898. [Homonym, Kunth, 1846.] 



Fieus planicostata lalifolia Lesquereux, U. S. Geol. and 

 Geog. Survey Terr. Ann. Rept. for 1872, p. 393, 

 1873; Tertiary flora: U. S. Geol. Survey Terr. Rept., 

 vol. 7, p. 202, pi. 31, fig. 9, 1878. [Lesqiiereux's 

 original figure is here reproduced as PI. XII, fig. 2.] 



Leaves thick, very large, 9 to 15 centimeters 

 long, 10 to 14 centimeters broad, from nearly 

 circular to short oblong, a little longer than 

 broad, heart-shaped at base, evenly rounded 

 at apex; margin perfectly entire; petiole short, 

 thick; leaf strongly palmately three-ribbed 

 from the apex to the petiole; the two lateral 

 ribs form an angle of about 40° with the cen- 

 tral or midrib and thence proceed nearly straight 

 to the margin high above the middle, sending 

 off from their outer side from 8 to 10 well- 

 developed, often somewhat irregular second- 

 aries, the lowest of which supports 6 to 8 

 tertiaries ; midrib naked for some distance above 

 the insertion of the lateral primaries, then 

 giving rise to three or four strong, alternate, 

 distant nerves on each side, which branch in 

 the same manner as the lateral nerves; sec- 

 ondary and tertiary nerves arching near the 

 margin by rounded loops ; nervilles very promi- 

 nent, usually simple, and curved or several 

 times subdivided so as to form small quad- 

 rangular meshes. 



When this form was first described by 

 Lesquereux he was in doubt as to whether it 

 should be ranked as a large, broad-leaved 

 variety of F. planicostata or regarded as speci- 

 fically distinct. In the "Tertiary flora," page 

 202, he reiterates this expression of doubt, but 

 as he had found only two leaves of this charac- 

 ter, he was inclined to regard it as only a 

 variety of F. planicostata. He remarks, how- 

 ever, that among very numerous examples of 

 F. planicostata there appeared to be no marked 

 variation from tlie normal size and shape, 

 whereas the species under consideration is 

 twice as large and has a heart-shaped base. 

 The nervation is of precisely the same charac- 

 ter in both. 



