1908] THIESSEN—DIOON EDULE 365 
spiral turns is more slender and folds over the next inner leaf more 
than does its mate (fig. 7). It will be observed that the girdle which 
is destined for that side of the leaf generally describes a longer curve 
through the cortex than the one destined for the other side. The 
phenomenon of girdling will become clearer when illustrated by a 
specific case. In fig. 6, taken from a young seedling, L:, L,, L,, 
and L, represent the first, second, third, and fourth leaves or primor- 
oa Lt, L?, L3, L4, the four strands of the first leaf; Li, L2, L3, L4, 
the strands of the second primordium. Lz? is the longest girdle of the 
first leaf and has its origin at the protoxylem group px’, on the side 
directly opposite the leaf to which it belongs, ascends for a short 
distance, then turns outwardly into the cortex and describes a wide 
horizontal curve, enters the longer and more slender edge of the 
leaf base, and ascends in the petiole in the dorsal left-hand portion, 
branching repeatedly in its further course. Trace Ls leaves the cen- 
tral cylinder near the protoxylem group px‘, ascends a short distance, 
Tuns upwardly and outwardly into the cortex, describes a horizontal 
curve in the opposite direction, enters that side of the leaf having the 
shorter sheathing base, ahd ascends in the dorsal or adaxial portion 
of the petiole, where it branches repeatedly in its further upward 
Course. From this it will be seen that the leaf trace L} pursues a longer 
Course than trace L+. Trace L? has its origin near the protoxylem 
Stoup px3, to the left, ascends for a short distance, runs out into the 
Cortex, makes a very slight horizontal curve (almost direct) into the 
leaf base, running outwardly, and then ascends on the ventral or 
abaxial left-hand portion of the petiole without further branching. 
Trace Ls has its origin near the protoxylem group px‘, ascends for 
4 short distance, runs outwardly (gradually ascending) with a slight 
curve into the leaf base, and finally ascends in the ventral or abaxial 
night-hand portion of the petiole without further branching. It will 
be seen that in the case of the two inner strands L3 makes a girdle of 
about 90°, while trace L? is approximately direct. 
bout the same condition occurs in the traces of the second leaf. 
Trace L} has its origin to the left and near the protoxylem group 
Px, ascends vertically for a short distance (but farther than the 
‘trands of L,), runs a short distance outwardly into the cortex and 
then makes a wide horizontal sweep, enters the leaf base on that side 
