30 FOSSIL FLORA OF THE SIERRA NEVADA. 



These two leaflets seem at first like a variable form of R. typhinoides. 

 They have, however, all the secondary veins percurrent to the point of 

 the distant more obtuse teeth, and this difference is marked enough to 

 authorize a distinct specification. The specimens are too obscure (the 

 details of the areolation being obsolete on account of a coating of var- 

 nish) to offer precise indication of their relation. They may even repre- 

 sent leaflets of a trilobate species, as by their outlines and nervation 

 they have a degree of likeness to the leaves of R. diversifolia, Torr. 

 and Gr., of Oregon. This one, however, has the leaflets comparatively 

 broader, and still more indistinctly denticulate ; they are intermediate in 

 characters between the former and the following species. 



Huhitat. — The specimens do not bear any reference number. They 

 seem to be from the same locality as that of the former species. Voy's 

 Collection. 



Rhus mixta, sp. nov. 



PL IX. Fig. 13. 



Leaves pinnate ; leaflets linear or ovate-lanceolate, obtusely pointed, more or less une- 

 quilateral at the round-cuneate base; borders distinctly ami distant!;/ serrate; 

 nervation subcamptodrome. 



The leaflets exposed upon the specimen appear to belong to the 

 same odd-pinnate leaf, the short oval ones being the terminal, and the 

 long, narrower, and linear representing the lateral ones. Though by 

 their facies they seem referable to a Cun/a, their nervation is that of a 

 Rhus, the secondary veins either curving under the teeth and entering 

 them by nervilles, or passing up directly to their points. These lateral 

 nerves are close, parallel, generally at an open angle of divergence, from 

 00° -70°, thick, deeply impressed, joined by fibrillar about in right angle. 

 All the details of areolation are obsolete. I clo not know of any more 

 marked relation to this species than that of Rhus typMna, Linn., which 

 it resembles by the linear form of the lateral leaves, and the close numer- 

 ous secondary veins of an equal angle of divergence. The fossil species 

 differs, however, by the broader shorter terminal leaflets being merely 

 obtusely pointed, and by the more distant teeth of the borders. 



Habitat. — Chalk Bluffs, California. Professor J. D. Whitney. 



