80 
to belong to the stem above the junction of the leaf trace 
and the root, and the same condition prevailed in older speci- 
mens that were studied. 
Fig. 10 shows three transverse sections of the young plant 
with the two leaves. The section ,a” is made at a point just 
below the stem apex. Two bundles are seen in the section be- 
longing, respectively to the first and second leaves. ‘Figures 
»b” and ,c’” represent sections taken from the same series at 
points lower down, and show the gradual apprcach of these 
two bundles which finally coalesce to form the single axial 
strand of the stem. 
Fig. 11 shows three sections of the central vascular cylinder 
of a somewhat older sporophyte taken at different heights. In 
the lower part of the plant there is a solid cylinder, the xylem 
arranged in a nearly continuous circle, as seen in section. 
Higher up (,b”), the bundle appears crescent shaped, and still 
higher separates completely into two distinct bundles. As the 
stem increases in diameter, the cross section shows an increased 
number of bundles arranged in a circle, and approximating the 
condition found in the adult stem. In the young plants the 
central strand inside of the hollow vascular cylinder of the 
older plant is not developed. Apparently in the young sporo- 
phyte of Kaulfussia there is no proper cauline stele, the whole 
vascular system being composed of united leaf traces, and from 
a preliminary study of the vascular system in Danaea, T have 
concluded that a similar state of things exists in that genus. 
I hope soon to make a study of this point in the young sp? 
rophyte of Marattia and Angiopteris as well. 
The young sporophyte at first shows neither the tannin cells 
nor the large mucilage ducts wich are so conspicuous in the 
older plant, but these are well developed while the plant is 
still quite small. 
