30 FOSSIL FLORA OF THE SIERRA NEVADA. 
These two leaflets seem at first like a variable form of LR. 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 £. 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. 
Habitat. — 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. 
PR LER go 13. 
Leaves pinnate ; leaflets linear or ovate-lanceolate, obtusely pointed, more or less wne- 
quilateral at the round-cuneate base; borders distinctly and distantly 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 Carya, 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 
60°-—70°, thick, deeply impressed, joined by fibrillze about in right angle. 
All the details of areolation are obsolete. I do- not know of any more 
marked relation to this species than that of Rhus typhina, 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. 
Halitat. — Chalk Bluffs, California. Professor J. D. Whitney. 
