48 
Groom . — On a New 
(3) Four to five layers of cortical parenchyma the cells of 
which have walls of cellulose. Most of these cells contained 
coiled mycorhizal hyphae , even so far as the endodermis. 
The central cylinder is very small. 
(4) The endodermis forms a characteristic layer of cells of 
the C-type with greatly thickened, stratified, and suberized 
inner walls (Fig. 5). The cells are elongated in the direction 
of the long axis of the root. There are no passage-cells ; 
and it is obvious that liquids cannot pass easily into the 
central cylinder from the parenchymatous cortex. 
(5) The pericycle forms a single well-defined layer of longi- 
tudinally elongated cells with lignified walls of average 
thickness. In longitudinal sections the nuclei are seen not 
to be elongated longitudinally, but more or less square. 
With the meagre supply of material, it was difficult to 
establish any clear facts as to the arrangement and differ- 
entiation of the narrow constituents lying within the 
pericycle. 
(6) Phloem (?). In transverse sections, at about four points, 
there were minute groups, each including three to four very 
narrow cells with thin walls of cellulose (Fig. 5 ,ph). They 
were all elongated longitudinally ; and some, at least, pos- 
sessed very long strap-like nuclei. I did not succeed in 
detecting sieve-tubes. 
Excepting these phloem-cells (?) all the remaining tissue 
within the pericycle is lignified. 
(7) Xylern . There are clearly marked conducting con- 
stituents represented by narrow tracheides with oval or slit- 
like bordered pits, or loose reticulate thickenings. Fig. 5 
shows that midway between the supposed groups of phloem, 
the cells abutting on the pericycle are smaller and more 
isodiametral than the cells contiguous to the phloem (?) ; they 
probably represent the small outer extremities of the rudi- 
mentary radial groups of xylem : for in longitudinal sections 
tracheides are seen in direct contact with the pericycle, as 
are also cells with oval nuclei. 
