280 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



The form and size are the same as those of the leaf referred to Biospyros 

 brachyscpala (pi. xl, fig. 7); Init the nervation is of a different type. But for 

 the branching of one of its nerves, it would be referable io R. Decl<e)ui,Iieer. 

 Habitat. — Golden, South Table Mountain, Colorado. 



Rliamnus! discolor, Lesqz. 



Plate LIT, Fig. 17. 



Jthamnus discolor, Lesqx., Anuu.!! Report, 1872, p. 31)8. 



Leaf oval, bro.adly cuneate to the petiole, very entire, nieniLr.anaccous ; nervition camptodrome ; 

 secondary nerves clotc, parallel, counicted by mimeroup, dibtiuct, obli(]ue uervilles. 



As for the former leaf, the generic relation of tliis one might be con- 

 tradicted. The leaf is much like that described and figured as Quercus 

 straminea (pi. .xix, fig. 7). But if the shape is the same, the nervation is far 

 different. All the veins are black; covered with a thin coating of coaly 

 matter, as if they had been originally villous. They are all simple, or without 

 any trace of branch, reaching straight to the borders on a more acute angle 

 of divergence, and without any trace of tertiary intermixed nerves, which 

 separate nearly all the secondary ones in the leaf of pi. xix. The texture 

 also seems to be more thick and compact. This Rliamnus is related to it. 

 hrevifoluis, Al. Br. (in Heer, Fl. Tert. Helv., p. 78, pi. cxxiii, figs. 27, 30), dif- 

 fering by the shape and the larger size 6f the leaves, which, by their form, 

 relate the species to R. Purshianus, D C, a species now living in Oregon. 



Habitat. — Black Buttes, Wyoming; very rare. 



K li a 111 n us C I « b u mi, Lesqx. 



Plate LlII, Pigs. 1-3. 

 Ehanmus Ckburni, Lesqx., Annual Report, 1872, pp. 381, 400.— Schp , Pal. y6g6t., iii, p. 611. 



Leaves soniewh.at tbick, but not coriaceous, very entire, elliptical or lanceolate, taper-pointed, 

 narrowed to a comparatively long, slender petiole; secondary veins close, parallel, scarcely curved in 

 traversing the lamina, forming a series of simple bows very near Ihe borders, joined by very close 

 nervilles. 



These leaves, like those of the following species, belong to the section 

 mentioned above, whose relation is considered by European authors as more 

 marked with Eiq)horhiacecp or Morece. The leaves are of large size, more or 

 less acutely pointed, with the base cuneate, and with numerous alternate 

 lateral nerves diverging about 40° from the narrow midrib. Fig. 3 resembles 

 fig. 5 of pi. xlii, described as a Co/iuis. Its lateral nerves are, however, closer, 

 about twice as numerous, not cuived or slightly so in passing up to the borders, 



