522 Shove.—On the Structure of the 
the arrangement must be examined in the case of some plant 
that has not undergone decay. 
With regard to the internal structure of the stem-stele, the 
chief point of interest is the anomalous position of the 
protophloem. 
The centrifugal growth of the phloem is contrary to that 
described for most other Ferns, and it would be of interest to 
examine the development of the steles in the other members 
of the Marattiaceae to determine whether in them a similar 
method of development is repeated. The histological structure 
of the stem-steles in Kaulfussia and Marattia has been 
described by Kuhn, but no mention is made of the proto¬ 
phloem ; this, however, is so indistinct in the mature bundles 
that, unless its position had been first determined in the young 
steles, its presence might well have been overlooked. 
The number and position of the protoxylem-groups has 
been worked out for a complete transverse section of the 
stem, and the mesarch and endarch structure of the steles has 
been further confirmed by the position of the spiral and 
reticulate tracheides as seen in longitudinal sections of the 
steles. 
In the apical regions of the stem the presence of several 
initial cells was satisfactorily demonstrated, but the exact 
number of these and their method of division still remain to 
be determined. 
Investigations into the structure of the roots on the plant 
examined show that these are of one kind and correspond 
in structure to the earth-roots described by Russow; the stem 
was apparently destitute of air-roots. 
Owing to the impossibility of obtaining the prothalli of 
Angiopteris , no examination could be made into the structure 
of the seedling stems ; such work is of course necessary to 
render complete the account of the stem-anatomy. 
