456 BOTANICAL GAZETTE , [DECEMBER 
yr and ¢. A section taken between cc and dd might show all the 
way from 4 to 12 strands, depending entirely upon the exact level 
of the section, and a section taken above dd might show from 6 to 8 
for the same reason. Slight variations in the origin of coincident 
laterals due to unequal nourishment would be shown in an odd 
number of traces. Returning to figs. 20-23, diagram 22 occurs 
about the level dd. Laterals from w and x have been given off to 
form p, but have not yet anastomosed. A lateral from z to form s 
has been separated from the parent bundle, but its mate from y is 
still intact within y. Meanwhile traces from x and z have already 
arisen for the formation of r and /, although their mates are still 
within the main bundles w and y. Hence the actual derivations 
are atypical in location, although the end results are the same, that 
is, 4 median strands (9, r, s, ¢) derived from uniting limbs of the 
4 original bundles (w, x,y,z). The section in fig. 23 shows a level 
above dd, where laterals are being derived from ¢ and w, y and 
$s, y and r, to form strands of tertiary rank, with laterals from w 
and p not yet derived. Already x and z have been broken up by 
a twofold bifurcation. ‘ 
Certain atypical traces were found in the study of the tissues of 
B. sagittata at this period in its development. In one series of sec- 
tions the laterals from x and # received a trace from below. Further 
observation showed this trace to end blindly at a lower level. In 
another series the lateral from z to s was found to give back certain 
strands to z before the lateral united with its mate from y. In such 
cases transverse sections alone would be difficult to use in tracing 
such bundle anatomy. In older stems and in the peduncle 8-24 
traces are derived, dependent on the amount of conduction required 
in these parts. 
Lear.—The leaf type of a-seedling is defined with reference to 
the number of traces in the blade which appear as separate entities 
at the origin of the leaf blade from the petiole. In his studies on 
some 50 seedlings of representative groups of Compositae LEE (10) 
has chosen Silphium perfoliatum as the type for Heliantheae, to 
which tribe B. sagittata belongs. The general superficial appear- 
ance of S. perfoliatum and the plant under consideration is very 
similar. Both seedlings are large and hardy, with no secondary 
