THE FLORA. 



159 



it is obviously so distinct from anything else in 

 these collections that it merits description. It 

 is very unlike either of the other Laramie forms 

 referred to Zizyphus — in fact, it belongs to 

 quite a different section of the genus. It is, 

 however, so well characterized, though it is 

 fragmentary, that there should be no trouble 

 in its subsequent recognition. 



Occurrence: Laramie formation, railroad cut 

 between old and new stations, Marshall, Colo., 

 collected by A. C. Peale, 1908. 



Order MALVALES. 



Family TILIACEAE? 



Apeibopsis? laramiensis Knowlton, n. sp. 



Plate VII, iigiire 4. 

 Apeibopsisf laramiensis Knowlton [nomen nudum], U. S. 

 Geol. Survey Bull. 696, p. SO, 19U). 



Leaf evidently membranaceous, broadly 

 ovate, at least 8 centimeters in length and 5.5 

 centimeters in width, abruptly rounded and 

 truncate at the base, apex destroyed but ap- 

 parently obtusely pointed; margin perfectly 

 entire; petiole 3.5 centimeters long, slender; 

 midrib straight, rather strong; secondaries 

 about 15 pairs, mostly opposite or subopposite, 

 thin, at an angle of 20° or 30°, close, parallel, 

 very little curved upward, disappearing just 

 before reaching the margin; finer nervation 

 obsolete. 



This species appears to be most closely re- 

 lated to Apeihopsis? discolor (Lesquereux) Les- 

 quereux,^* from Black Buttes, Wyo., but it 

 differs in its more truncate base, thinner nerva- 

 tion, and more numerous secondaries. 



The generic reference of both these species is 

 more or less questionable, as Lesquereux 

 pointed out when discussing his species, but 

 they are apparently congeneric and may remain 

 for the present with the question mark to indi- 

 cate this doubt. 



Occurrence: Laramie formation, Leyden 

 Gulch, about' 6^ miles north of Golden, Colo., 

 collected by A. C. Peale. 



Order UMBELLALES. 



Family CORNACE.ffi. 



Cornus suborbifera Lesquereux. 



Plate XIV, figure.? 2, 2a (type). 

 Cornus suborbifera Lesquereux, Tertiary flora: U. S. Geol. 

 Survey Terr. Kept., vol. 7, p. 243, pi. 42, figs, 2, 2a, 

 1878; U. S. Geol. and Geog. Survey Terr. Ann. 



« Lesquereux, Leo, The Tertiary flora: U. S. Geol. Survey Terr. Rept., 

 vol. 7, p. 259, pi. 46, figs. 4-7, 1878. 



Rept. for 1S76, p. 512, 1878. [Lesquereux's figure 

 of the type i.s here reproduced.] 

 Cornus orhifera Heer. Lesquereux, U. S. Geol. and Geog. 

 Survey Terr. Ann. Rept. for 1873, p. 402, 1874; 

 idem for 1876, p. 512, 1878. 



The type specimen of this species was found 

 in the United States National Museum collec- 

 tions (No. 353) under the name Cornns orhifera 

 Heer, with which it was at first identified. Les- 

 quereux explains, however, in the "Tertiary 

 flora," page 243, that on the advice of Saporta 

 he decided to give it a new name, although he 

 found difficulty in distinguishing it from the 

 European species. The type of Cornus subor- 

 bifera is very imperfect and hardly admits of 

 close comparison. 



This species is apparently related to Cornus 

 impressa Lesquereux, from the Denver forma- 

 tion of Golden, Colo., but appears to differ es- 

 sentially in the secondaries emerging at a much 

 more open angle. 



Occurrence: Laramie formation. Golden, 

 Colo., in the white sandstone. 



Cornus praeimpressa Knowlton, n. sp. 



Plate XIV, figure 5; Plate XIX, figure 2a. 



Cornus praeimpressa Knowlton [nomen nudum], U. S. 

 Geol. Survey Uull. 696, p. 195, 1919. 



Leaf evidently fii-m in texture, elliptical, ap- 

 parently rounded or perhaps truncate at the 

 base and abruptly rounded at the apex to a 

 short obtuse point; length about 8 centimeters 

 and width 5 centimeters; midrib very thick, 

 especially below, perfectly straight; secondarie? 

 about 10 pairs, mainly alternate, at an angle of 

 about 50°, slightly curved upward, campto- 

 drome, arching just inside the margin; nervilles 

 numerous, strong, mainly unbroken, at nearly 

 right angles with the secondaries; finer nerva- 

 tion obsolete. 



This form is based on the single example from 

 Cowan station here figured. It is very well 

 characterized by its regular elliptical outline, 

 very thick midrib, relatively thin secondaries, 

 and nervilles at nearly right angles to the 

 secondaries. 



This species, as its name implies, is most 

 closely related to Cornus impressa Lesquereu.x, " 

 the type of which came from Mount Bross, 

 Middle Park, Colo., where it was found in beds 

 believed to be of Denver age. So far as known 



'5 Lesquereux, Leo, The Tertiary flora: U. S. Geol. Survey Terr. Rept., 

 vol. 7, p. 343. pi. 43, fig. 3, 1878. 



