48 BULLETIN OF THE 
lanceolate above, generally palmately trinerved, teeth of the borders large, 
equal, sharply pointed. 13 specimens. 
41. P. Nebrascensis, var. longifolia, Lx. Leaves large, oblong-ovate, rounded 
at base, five-nerved ; lateral primary nerves ascending to above the middle, 
scarcely curved inside, much branching ; secondary nerves three or four pairs, 
at a great distance from the base, camptodrome or craspedodrome, with their 
divisions effaced at the borders which are cut in obtuse large teeth. The leaves 
are longer, lanceolate from below the middle, 7; to 11 em. long, 4 to 7 cm. 
broad below the middle ; the teeth are large, round, equal, marked from near 
the base ; the petiole is long and slender.’ 15 specimens. 
42. Populus tenwinervata, sp. nov. Leaves comparatively small, round or 
ovate, broadly cuneate or rounded at base, palmately five-nerved ; inner pri- 
mary nerves curving inward and ascending near the apex ; those of the out- 
side also curving and ascending to the middle, all camptodrome, thin but 
distinct ; borders irregularly dentate, the teeth unequal and pointed ; nervilles 
distinct, obliquely joined in the middle. 
The leaves resemble those of a Ficus, being, in their facies, like those of Ficus 
crenata, Ung., which, however, has not distinct nervilles. They have a still 
more marked likeness to those of Populus latior-transversa, Heer, as figured 
by Ludwig in Paleont., V., Plate XXVI. fig. 3. The petiole is thick. 34 
specimens. 
43. Populus crenata, Ung., considered by Schimper a var. of P. mutabilis, 
Heer. The leaves are referable to the species as it is figured by the author, 
Fl. of Sotzka, Plate XV. fig. 6, being small, oval, rounded, and trinerved at 
base, the primary lateral nerves at an acute angle of divergence, not much 
curved inward, the borders with large unequal teeth, the substance coriaceous 
and the surface polished. 17 specimens. 
44, Populus attenuata, Al. Br. 2 specimens. 
Plataneze. 
45 and 46. Platanus Guillelme, Goepp., and P. aceroides, Heer. It is ex- 
tremely difficult to separate the species. The description of Heer, Fl. Alask., 
p- 473, merely defines the leaves of P. Gwillelme as undivided or merely sub- 
lobate, acutely dentate, narrowed into a short petiole; secondary nerves at an 
acute angle of divergence ; and he remarks in the explanation, that the leaves 
of Disco which he refers to the species are tapering to the petiole, slightly lobed 
or not at all, and have short teeth. According to this, most of the very numer- 
ous specimens obtained at Golden are referable to P. Guillelme. I refer to 
P. aceroide those with more open primary lateral nerves and of a more solid 
consistence. The determination is rendered more uncertain by the generally 
fragmentary state of the specimens. 76 specimens. 
47. Platanus Haydenii, Newby. A beautiful specimen, No. 508 of the list, 
appears referable as a variety to this species. The leaf is oval in outline, tri- 
nerved from above the decurring base; the lobes, five, short, obtuse at the apex 
