THE FLOfeA. 



133 



The fortunate discovery of a number of well 

 preserved leaves of this species in the coarse 

 sandstones at Hoyt's coal mine, near Golden, 

 Colo., and also at Marshall's coal mine, in 

 Boulder County, Colo., makes it possible to 

 arrive at a better understanding of this form, 

 which it now seems best to raise to full specific 

 rank. It turns out that the smallest leaf that 

 has been found is the original type from Black 

 Buttes, 89 while the largest is fully 15 centi- 

 meters long and 14 centimeters broad. They 

 are undoubtedly very closely allied to F. 

 planicostata but differ from it in being uni- 

 formly at least twice the size and without 

 intermediate forms and in being heart-shaped 

 at the base. This Species is also closely allied 

 to F. speciosissima Ward, 00 from Point of 

 Rocks, Wyo., which differs merely in being 

 more markedly heart-shaped at the base and 

 in having the nervilles joining the arches of 

 the secondary and tertiary nervation to the 

 margin, either character being of special im- 

 portance. Ficus speciosissima is also slightly 

 inequilateral, thus approaching certain forms 

 of F. tiliaefoUa. 



The figured type of F. latifolia (U. S. Nat. 

 Mus. No. 278) is from Black Buttes, Wyo. 

 The other type specimen is said to have come 

 from Golden, Colo., but as it can not be found 

 in the Museum collections I can not state 

 whether it came from the true Laramie or the 

 Denver formation, but inasmuch as all the 

 recent collections from Golden containing it 

 are in the true Laramie, it is probably a lower 

 or true Laramie species. 



As the specific name latifolia proved to be a 

 homonym of a living species (Kunth, 1846), it 

 has been necessary to give this form a new 

 name. It is named in honor of Prof. T. D. A. 

 Cockerell, of Boulder, Colo., a well-known 

 student of the Colorado fauna and flora. 



Occurrence: Post-Laramie (in my opinion), 



Black Buttes, Wyo. Laramie formation, 



Hoyt's coal mine, near Golden, and Marshall's 



coal mine, both in Boulder County, Colo. 



Ficus planicostata magnifolia Knowlton, n. var. 



Plate X, figure 3. 



Ficus planicostata magnifolia Knowlton [nomen nudum], 



U. 8. Geol. Survey Bull. 696, p. 285, 1919. 



Similar to the type but much larger, reach- 

 ing 14 centimeters in length and 9 centimeters 



s» Lesquereux, Leo, op. cit. (Tertiary flora), pi. 31, fig. 9. 

 »o Ward, L. F., Types of the Laramie flora: U. S. Geol. Survey Bull. 

 37, p. 39, pi. 21, flg. 3, 1887. 



in width, slightly more pointed above and less 

 evidently truncate below, but otherwise much 

 the same. 



This form is described as new with some hesi- 

 tation. It clearly belongs to that group of 

 species which includes Ficus planicostata, F. 

 cocker elli, F. speciosissima, F. leei, and others. 

 Ficus cockerelli differs from it in being very 

 much larger and in having a deeply cordate 

 base, which produces marked differences in 

 the nervation; F. leei differs in size and shape, 

 being smaller and more elongate, and in a 

 number of minor particulars of nervation. 



It is of course quite true that difference in 

 size is an unreliable criterion on which to base 

 specific or even varietal distinction, provided 

 there is agreement in other particulars, but in 

 the present case it is thought that the differ- 

 ences > are sufficient to warrant keeping these 

 leaves from identification with the typical F. 

 planicostata. 



Occurrence: Laramie formation, Marshall, 

 Colo., half a mile south of railroad station, in 

 first draw north of white sandstone bluff, just 

 above the highest coal of the region, collected 

 by F. H. Knowlton and G. C. Martin, 1908. 



Ficus praeplanicostata Knowlton, n. sp. 



Plate XXII, figure 2. 

 Ficus praeplanicostata Knowlton [nomen nudum], U. S. 

 Geol. Survey Bull. 696, p. 285, 1919. 



Leaf coriaceous, elliptical-obovate, appar- 

 ently rounded below to a more or less distinctly 

 wedge-shaped base and narrowed above in 

 like degree to an obtusely acuminate apex; 

 margin perfectly entire ; midrib rather slender, 

 perfectly straight; apparently three-ribbed 

 from or near the base, the lateral ribs slender, 

 at an acute angle, somewhat curving upward, 

 ascending nearly to the top of the blade, and 

 joining the lowest secondary just within the 

 margin; lateral ribs with seven or eight secon- 

 dary branches on the outside, each of which 

 arises at an . acute angle, curves slightly up- 

 ward and joins the one next above just at the 

 margin; secondaries on the midrib four or five 

 pairs, scattered, strongly alternate, each pass- 

 ing upward practically parallel to the lateral 

 ribs and joining the one next above, the upper 

 pair arching completely around and joining 

 the midrib near the apex of the blade; nervilles 

 very numerous and conspicuous, mainly per- 

 current but also broken, approximately at 

 right angles to the midrib. 



