1 8 Tansley and Chick. — Notes on the 
quite thin horizontal or slightly inclined end-walls, and seem 
always quite destitute of starch. This pericyclic layer may 
be as much as two or three cells thick, and there may be no 
very sharp line of separation between it and the stereids of 
the central strand. It is often interrupted in places, so that 
genuine stereids come to abut directly on the endodermis. 
Thin-walled hydroids also are frequently mixed with the 
pericyclic cells, and may likewise abut upon the endodermis 
(cf. Haberlandt, op. cit, Taf. XXI, Fig. 18). 
Each pericyclic arc follows the broad lobe of the central 
mass round its angles, and is continuous with the tissue 
lining the furrows. Haberlandt says nothing about the strands 
of tissue occupying the three furrows. Bastit calls them 
‘ secteurs pericycliques/ and remarks that they scarcely differ 
from the tissue immediately external to them (i. e. the inner 
part of what we have called the radial strands). He also 
says, however, that the tissue in the furrow ‘ presents the 
same characters as the elements of the pericyclic zone of the 
aerial stem. 5 Since by ‘pericyclic zone of the aerial stem 5 
Bastit refers to Haberlandt’s leptom, this last statement, 
together with the general root-like organization of the rhizome, 
suggested to us that sieve-tube-like cells might possibly be 
found in the furrows. This is actually the case. The centre 
of the bay is occupied by a little group of from six to eight 
polygonal cells with light yellow walls (lept . , Figs. 12, 18, 19). 
The two innermost of these are commonly larger than the 
others, and are separated by a particularly thick radial wall 
(Fig. 17). On transverse section these cells often possess 
thick granular contents giving proteid reactions, and so far 
as we have observed never contain starch. In longitudinal 
section they often show the perfectly typical characters of 
Haberlandts ‘ siebrohrenartigen Zellreihen ’ (Figs. 15, 16, 1 6 a). 
It does not appear that Bastit recognized this fact, notwith- 
standing his above-quoted statement. 
This little group of sieve-tube-like cells ( leptoids as we may 
call them) is surrounded by starchy parenchyma, to which 
we may apply Troschel’s term amylom. To the inside and 
