1917] FAUST—RESIN SECRETION 457 
roots up to this period of development. In writing about the 
bundle strands of this type LEE states as follows: 
As usual in this order the single vascular bundle at the apex of the coty- 
ledon first divides into 3, after which, in correspondence with the large size of 
the cotyledons, each main strand gives off a large number of smaller bundles. 
At a lower level, these begin to re-fuse with the larger strands, and at the base 
of each cotyledon only 5 vascular strands remain, a large-median one and two 
smaller laterals on either side. In the pronounced cotyledonary tube the 
extreme lateral and smallest bundles fuse with the corresponding bundles from 
the other cotyledon, and the composite structure produced, after decreasing 
in size, moves around and joins on to one of the remaining strands. At a still 
lower level in the cotyledonary tube, the remaining lateral bundles fuse in 
pairs, so that 4 canal vascular strands enter the hypocotyl. 
Upon examination of seedlings of B. sagittata it is evident that 
neither the cotyledons (figs. 22-24) nor the first true leaf (fig. 6) 
possess bundle traces exactly corresponding to the type for the 
Heliantheae. There are considerably more than 5 strands for the 
region above the origin of the blade (fig. 23), but at a level just 
below the cotyledons in the cotyledonary collar (fig. 24, level dd) 
only 6 strands are found, ‘although in certain sections even below 
this level (fig. 22) a greater number is indicated, due to peculiarities 
of transverse anastomoses. Even the true leaf (fig. 6) shows only 
3 bundle strands at the origin of the blade from the petiole. It may 
be said, therefore, that for B. sagittata we have a type of bundle 
anatomy of somewhat fewer strands than for Silphium perfoliatum. 
With these exceptions it has a general resemblance to the tetrarch 
anatomy of the Heliantheae. 
RESINIFEROUS DUCTs.—A root of a young seedling with coty- 
ledons not yet outspread shows clearly the resin secretion from the 
protoxylem outward through the cortex. There are large drops of 
resin at the time the endodermis begins to take on suberized thick- 
enings, yet at this stage no resin ducts have formed. Not until the 
seedling is somé 60 days old do the ducts begin to form in the root. 
The development, although surely determinetl beforehand, does not 
occur until after resin formation. The method of development is 
schizogenous. First a periclinal division occurs in the endodermal 
cell opposite a group of tracheids. This is followed by an anticlinal 
division, so that 4 cells arise from the original endodermal cell 
