THE FLORA. 



157 



Rhamnus clebumi was reported by Les- 

 quereux 50 from the Laramie at the old France- 

 ville mine, near Colorado Springs, but it is not 

 found in the recent collections from that place. 

 The present leaf from Popes Bluffs is hardly 

 one-fourth the size of the ordinary leaves of 

 this species and, moreover, differs in shape, 

 being narrower. The absence of the basal por- 

 tion makes it impossible to decide whether to 

 assign this leaf to Rhamnus clebumi or to 

 Rhamnus goldianus, and the most that can be 

 said is that the present specimen is of the 

 same type as these species. Its smaller size 

 and narrower outline suggest that it probably 

 is neither of these species, though obviously 

 allied. 



Occurrence: Laramie formation, Popes 

 Bluffs, west of Pikeview, Colo. (sec. 14, T. 13 

 S., R. 67 W.), collected by A. C. -Peale and 

 M. I.. Goldman, 1908. 



Paliurus zizyphoides Lesquereux? 



Paliurus zizyphoides Lesquereux, U. S. Geol. and Geog. 

 Survey Terr. Ann. Rept. for 1872, p. 397, 1873; 

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

 vol. 7, p. 274, pi. 51, figs. 1-6, 1878. 



This form was established on material from 

 Black Buttes, Wyo., a part of which, at least, 

 is still in the collections of the United States 

 National Museum (cf. No. 416a). In the same 

 connection Lesquereux wrote as follows: "The 

 same species, represented by a smaller leaf, 

 has been found at Erie." The Museum collec- 

 tion does not contain a specimen from Erie, 

 nor has this form been noted in any of the 

 recent collections from that place, and it is 

 consequently questioned as a Laramie species. 



Occurrence: Post-Laramie (in my opinion), 

 Black Buttes, Wyo. (types). Laramie forma- 

 tion ?), Erie, Colo. 



Zizyphus coloradensis Knowlton, n. sp. 



Plate XV, figure 5. 



Zizyphus coloradensis Knowlton [nomen nudum], U. S. 

 Geol. Survey Bull. 696, p. 660, 1919. 

 Leaf apparently rather thin in texture, ellip- 

 tical or slightly ovate-elliptical, obtusely wedge- 

 shaped at the base, apparently about the same 

 shape at the apex; margin entire below, pos- 

 sibly slightly toothed above; five-ribbed, the 



m Lesquereux, Leo, IT. S. Geol. and Geog. Survey Terr. Ann. Kept. 

 for 1S73, p. 203, 1874. 



85344— 22 11 



central or midrib stronger than the others, ap- 

 parently with two or three secondaries high 

 in the upper part; inner pair of ribs nearly as 

 strong as the midrib, passing up well toward 

 the apex of the blade; lower or outside ribs 

 slender, possibly arising from the basal portion 

 of the inner ribs, not reaching for more than 

 half the length of the blade; all finer nervation 

 effaced. 



Only a single specimen of this form has been 

 found, and this has lost much of the apical 

 portion. It was presumably about 6 centi- 

 meters long and 2.5 centimeters wide. It is 

 preserved on a very soft sandstone, and not 

 many of the details of nervation can be made 

 out except the ribs. 



This species may be only a small, narrow leaf 

 of Zizyphus hendersoni, but it appears to be a 

 thinner leaf and is possibly toothed in the 

 upper portion. It has also some resemblance 

 to Zizyphus cinnamomoides Lesquereux, 51 from 

 the Green River formation, but the latter is 

 smaller, strongly toothed nearly to the base, 

 and only three-ribbed. 



Occurrence : Laramie formation, Popes Bluffs, 

 west of Pikeview, Colo. (sec. 14, T. 13 S., R. 67 

 W.,) collected by A. C. Peale and M. I. Gold- 

 man, 1908. 



Zizyphus hendersoni Knowlton, n. sp. 



Plate XV, figures 1, 2. 



Zizyphus hendersoni Knowlton [nomen nudum], U. S. 

 Geol. Survey Bull. 696, p. 660, 1919. 



Leaf evidently firm in texture, ovate or ovate- 

 elliptical, rather abruptly rounded to the 

 slightly wedge-shaped base; apex not well pre- 

 served but apparently rather obtuse; margin 

 perfectly entire; petiole stout, at least 1 centi- 

 meter long; three-ribbed, or in effect five- 

 ribbed, the petiole splitting into approximately 

 three branches or ribs, and just as they leave 

 the wedge-shaped basal portion of the blade 

 each of the lateral ones gives rise to a strong 

 secondary "branch which simulates a rib, the 

 five about equally dividing the area of the 

 blade; middle rib straight, with several secon- 

 dary branches in the upper part;, next pair of 

 ribs about as strong as the midrib, ascending 

 well toward the apex of the blade, each with 



" Lesquereux, Leo, The Tertiary flora: U.S. Geol. Surrey Terr. Eept., 

 vol. 7, p. 277, pi. 52, flgs. 7, 8, 1878. 



