340 
points out, 1t 1s very difficult to obtain strictly median sections 
of even a rather short root. The root was cut a little obliquely 
in most of the cases, so that the initials could not be made out 
satisfactorily. West (41) found that in the Marattiaceae 
the number of root initials depended on the bulk rather than 
on the age of the root. However, there is no question that in 
the case of B. obliquum as in B. virginianum and in B. lunaria 
the root initial consists of a single apical cell. 
The development of the vascular bundle must begin at a 
very early stage. In all the cases examined, there was already 
an elaborate vascular system in the first root. In two plants 
the bundle appeared to be monarch (Fig. 6). The place of the 
proto xylem was, in these cases, not very clear. It is probably 
exarch. The irregular behavior of the proto xylem is a typical 
feature in Botrychium (Lang (22), and Campbell (9). The 
proto phloem was very conspicuous by its shrunken cells which 
gave the appearance of being thick-walled. The xylem con- 
sisted of spiral tracheids without conspicuous pits:; the phloem 
of cells with a dense protoplann, often with conspicuous nuclei. 
The endodermis was not easily distinguishable. 
In the other five plants, the root was diarch, xylem and 
phloem alternating (Fig. 7). There was a pericycle about 2—3 
layers thick and a very conspicuous endodermis. This is pro- 
bably the normal condition. An older stage is represented by 
Fig. 8. The phloem tends to surround the xylem, which has 
become a solid mass. This is the condition of the stele imme- 
diately below the place where the leaf trace coalesces with the 
root trace (Fig. 9). The phloem surrounds the xylem entirely. 
The latter is medullated. According to Bower (4) this medul- 
lation in Botrychium is intrastelar and depends on the nourish- 
ment of the young plant. In B. obliquum, however, this is not 
the case. Medullation below the junction of leaf and root 
traces could never be found. The pith is not of intrastelar 
origin, but simply an inclusion of parenchyms between root 
trace and leaf trace. The leaf trace (fig. 10) is a collateral 
