Populus. AMENTACEA:. 11 
The only leaf seen of this species is four and a half centimeters long, 
two and a half centimeters broad in the middle, exactly elliptical-oval, 
with borders minutely but distinctly crenato-serrulate. The divergence 
of the lateral veins is about 60° in joining the deep narrow midrib; but 
they soon curve toward the borders in simple festoons, narrowing the 
angle of divergence from the middle upwards. These lateral veins are 
close, twelve pairs, parallel, thin, but deeply and distinctly marked like 
the nervilles which unite them in right angle, and also the short inter- 
mediate tertiary veins. This leaf has distinctly the characters of the sec- 
tion Cinerascentes or Caprew, of the living Willows, and is closely related 
to S. capreeoides, Anders., of the California flora. 
Habitat. — Chalk Bluffs, California. Voy’s Collection. 
POPULUS, Linn. 
Populus Zaddachi, Heer. 
Pl. VII. Figs. 1-8. 
Leaves very variable in size, ovate, more or less acutely and gradually pointed, round or 
cordate at the base ; borders crenate ; nervation five to seven palmate, generally from 
the top of along slender petiole ; lower lateral nerves at an open angle of divergence ; 
the inner ones more acutely oblique, and ascending to near the upper part of the 
leaves, sometimes to near the point. 
Populus Zaddachi, Heer, Flor. Foss. Arct., L, p. 98, Pl. VI. Figs. 1-4; XV. Fig. 10; IIL, p. 468, Pl. 
XLII. Fig. 15a; XLIV. Fig. 6. Fl. Foss. Alask., p. 26, Pl. Il. Fig. 5a. Mioc. Fl. Spitz., p. 
55, Pl. II. Fig. 13c; X. Fig. 1; XI. Fig. 8d. Mioc. Balt. Fl. p. 30, Pls. V., VI, XII. Fig. 1. 
This species is very distinct, though variable in the form and size of 
its leaves. Our specimens represent these leaves from four to fifteen cen- 
timeters long, and from two to nine and a half centimeters broad. They 
are generally gradually enlarged from the point to near the base, where 
they become rounded or cordate to the petiole; but sometimes in nar- 
rower leaves, as in Fig. 6, they are attenuated to the base. The bor- 
ders are more or less deeply serrato-crenate, the teeth being either acute, 
as in Figs. 2 and 8, or very obtuse, as in Figs. 1 and 5. The petiole is 
slender, and of medium length. In Fig. 8 it seems very long; if, how- 
ever, the plicature at the base of the specimen is really from a part of 
the petiole of the same leaf, this would indicate a length of fourteen 
to fifteen centimeters, equal to that of the leaf itself. The petiole of 
