378 Boodle . — Anatomy of the Schizaeaceae. 
phloem. If normal, this may be compared with ‘cavity- 
parenchyma.’ 
At the node a segment of the xylem-ring separates for the 
leaf-trace, and carries with it the phloem on its outer side. 
The leaf-trace is seen cut rather obliquely in Fig. 12. In 
6\ dichotoma the leaf-trace is seen separated from the xylem 
and phloem of the stem in Fig. 11, but still enclosed by the 
endodermis. Fibres occur in the leaf-trace. In the diagram, 
Fig. 15, the leaf- trace surrounded by its own endodermis is 
on its way out through the cortex, and the endodermis of 
the stele has dipped into the leaf-gap as far as the inner limit 
of the xylem. As far as was observed, the pith remains 
separated from the cortex by the endodermis in the nodal 
region. The xylem of the leaf-trace becomes detached from 
the xylem of the stem at one end first. In S. fisttdosa the 
leaves are dorsal and apparently distichous, but in the speci- 
men described above as preparing for dichotomy the phyllo- 
taxy was 
In S. fisttdosa some of the leaf-traces in the cortex had 
an arched xylem-mass, with its convexity directed outwards. 
This type of structure is an approach to what is found in 
Anemia. The petiolar bundle resembles that of digitata . 
SCHIZAEA, root. 
In the root of Schizaea 'digitata there are only three layers 
of cells outside the endodermis. The outermost of these is 
the piliferous layer, and often peels off in the old root, then 
follows one layer of thin-walled cortex, and one layer of cells 
with their inner and radial walls very strongly thickened. In 
old roots the stratification of these walls is remarkably dis- 
tinct. The endodermal cells are flattish. Both pericycle, 
endodermis and the layer of sclerotic cortical cells usually 
consist of six cells each, but sometimes of eight or nine cells, 
especially in the case of the pericycle. The xylem forms 
a typical diarch plate, with two large tracheides in the 
metaxylem. The structure is nearly identical with that 
