402 BOTANICAL GAZETTE [DECEMBER 
thus sorediatus, and Baccharis pilularis, shrubs of the Palo Alto 
neighborhood, of frequent occurrence and reasonably independent 
as to altitude, soil, and exposure. As a further limitation, this account 
is confined with a single exception to the leaves of these plants; varia- 
tion in other features—for instance in the scales of the cup of Quercus 
—is not less conspicuous. 
QUERCUS CHRYSOLEPIS Liebmann. 
The leaves of oaks are exceedingly variable everywhere, but the 
differences between the leaves of this species on the same tree, or on 
neighboring trees, are conspicuous even in such a genus. igs. 1-3 
QDPODOCOGs 
oma HoonoQOH9 
PAVGOOOOY 
aves on 
Fic. 1.—Quercus ckrysolepis: a, alternate leaves on a branch; }, all the le 
a twig; ¢, all the leaves on a twig. In all series from left to right is towards the apex. 
are from neighboring trees, growing in the mountains back of Stan- 
ford University. Each tree had a well-defined leaf character, 
these outlines, each representing leaves of one season’s growth on one 
axis, indicate. The venation of the leaves on each tree was as charac- 
teristic as the outline. As a rule, older trees have more entire leaves, 
but this is not at all constant; all my specimens are from acorn-bearing 
trees. All the leaves figured grew on well-illuminated parts of the 
trees. In the three trees furnishing these leaves the variation 1 leaf- 
character was an attribute of the entire tree, and must therefore have 
occurred at a time in the tree’s history when it or the stage ™ ‘in 
ancestry where the variation occurred was a single cell, or (possibly) 
