152 



LARAMIE FLORA OF THE DEN\T:R BASIN. 



however, some of the abruptly pinnate leaves 

 of P. mutica Frirk and Meyer, also from 

 southern Europe. Most of the leaves of P. 

 mutica are odd-pinnate, at least on the speci- 

 men preserved in the herbarium of the United 

 States National Museum, yet now and then 

 one is found which is abruptly pinnate. They 

 have the same shape and arrangement as ob- 

 served in the fossil. The nervation is also 

 strikingly like that of the fossil species. 



I have not been able to see the only American 

 species of the genus — P. mexicana Humboldt, 

 Bonpland, and Kunth, of Mexico and possibly 

 southern Texas, but it is described as having a 

 winged petiole and must differ considerably 

 from the fossil under consideration. 



A number of fossil species of Pistacia have 

 been described, all of which differ more or less 

 from P. hollicki. Thus, P. bohemica Ettings- 

 hausen,^' from Bilin, has much the same shape 

 but is twice as large and differs in nervation. 

 Certain of the detached leaflets of P. miocenica 

 Saporta,'* from the "Bassin de Marseille," are 

 very much like the lateral leaflets of P. hollicki, 

 though broader and somewhat less inequi- 

 lateral. The other described fossil species ap- 

 proach the living P. lentiscus Linne or P. 

 terebinthinus Linne. 



I have ventured to name this species in honor 

 of Dr. Arthur HoUick, in partial recognition of 

 his kindness in placing this material at my 

 disposal. 



Occurrence: Laramie formation, Erie, Colo., 

 collected by N. L. Britton about 1885. 



Family ILICACEAE. 

 Hex laramiensis Knowlton, n. sp. 



Plate XXIV, figures 4-7. 



Ikx laramieTms Knowlton [nomen nudum], U. S. Geol. 

 Survey Bull. 696, p. 326, 1919. 



Leaves coriaceous, oval, rounded at the base, 

 acute at the apex, the margin provided with 

 scattered, upward-pointing, spiny teeth; mid- 

 rib rather slender; secondaries four or five pairs, 

 alternate, open, camptodrome, arching some 

 distance inside the margin and each joining the 

 one next above, with branches from the outside 

 entering the teeth; nervilles obscure but ap- 

 parently percurrent. 



" Die lossUe Flora des Tcrtiilrbeckens von Billn: K. Akad. Wlas. Wien 

 Denkschr., vol. 29, p. 49, pi. 50, fig. 25, 1869. 



" Annates sci. nat., 5th ser., Botanique, vol. 9, p. I**, pi. 6, figs. 4-6, 

 1868. 



These well-characterized leaves are broadly 

 oval, 3.5 centimeters long and about 2 to 2.5 

 centimeters wide. The margin is remotely 

 spiny-toothed above the lower third of the 

 blade, the teeth pointing upward and separated 

 by rounded sinuses. The camptodrome second- 

 aries have outside branches entering the teeth, a 

 well-known character of the genus Ilex. 



There can be little or no question of the cor- 

 rectness of referring these leaves to Ilex. 

 Among the several living species they un- 

 doubtedly approach most closely /. opaca 

 Alton, the well-known holly of the eastern 

 United States. This living species differs in 

 having the spiny teeth outward-pointing and in 

 having more numerous secondaries. The camp- 

 todrome arrangement of the secondaries with 

 the branches entering the teeth is very like the 

 arrangement in the fossil under consideration. 



Among fossil forms the present one has some 

 resemblance to Ilex quercifolia Lesquereux,^° 

 from Florissant, Colo., which, however, differs 

 in being obovate, with irregular teeth and more 

 numerous secondaries, which enter the teeth 

 directly. 



Occurrence: Laramie formation, Erie, Colo., 

 collected by N. L. Britton about 1885. 



Order RHAMNALES. 



Family RHAMNACEAE. 



Ceanothus eriensis Knowlton, n. sp. 



Plate XXVI, figures 3-6. 



Ceanothiis eriensis Knowlton [nomen nudum], U. S. Geol. 

 Survey Bull. 696, p. 151, 1919. 



Leaves evidently thick and coriaceous, 

 elliptical or broadly oval, rather abruptl)' 

 rounded to the base and in about equal degree 

 to the obtuse or abruptly acuminate apex; 

 margin entire for lower third, then finely 

 serrate; nervation craspcdodromc, consisting 

 of a strong, straight midrib ami three or four 

 pairs of strong, opposite or subopposite second- 

 aries, the lower j)air nearly as strong as the 

 midrib and arising at or very near the base of 

 the blade, each of the lower secondaries with 

 three or four rather remote, occasionall}' 

 forking branches on the lower side; the lower 

 pair of secondaries, which arise at an angle 

 of about 45°, pass upward for a little more than 



» Lesquereux, Leo, The Cretaceous and Tertiary floras: U. S. Geol. 

 Survey Terr. Kept., vol. 8, p. 186, pi. 38, figs. 2-5, 1S83. 



