498 
Tans ley and Lulham. — A Study of the 
TABLE SHOWING THE DIFFERENT STAGES OF PROGRESSIVE 
COMPLICATION IN THE RHIZOME AND LEAF-TRACE. 
(i) The young plants . 
Stage. 
Plants 
in which 
it occurs. 
Rhizome. 
Leaf-trace. 
Internode . 
Node . 
I. 
A, 
node i. 
Protostelic structure ; no 
distinguishable phloem. 
As in internode. 
Simple, like stele of 
stem. 
II. 
A, 
node 2. 
Lindsaya- type. 
Internal and external 
phloem in continuity. 
‘ Concentric ’ ; phloem 
mainly adaxial. 
III. 
A, 
node 3. 
B. 
Lindsay tf-type, with scat- 
tered endodermal cells 
in internal phloem. 
As in II, with local 
thickening of edge of 
‘ xylem-gap.’ 
* Concentric ’ ; gutter- 
shaped strand. 
IV. 
D. 
Lindsaya-type, with in- 
ternal (often scattered) 
endodermis, and free in- 
ternal xylem-strand. 
Internal xylem - strand 
joining external xylem. 
‘ Concentric ’ ; kidney- 
shaped strand. 
V. 
E, 
nodes 1, 2. 
Solenostele with local 
internal dilatation. 
As in internode. 
Closed ring in cross-sec- 
tion, with sclerized pith. 
VI. 
E, 
nodes 3- 
9, and 
13-14- 
Solenostele with internal 
xylem-strand often free 
(separated from external 
xylem by phloem and 
also often by endoder- 
mis) = second cylinder. 
Internal strand in con- 
nexion with external 
xylem at node. True 
leaf-gap sometimes pre- 
sent (diagram). 
Variable in structure. 
Sometimes a closed ring 
with sclerized pith, with 
or without internal 
endodermis, and xylem 
interrupted on adaxial 
side ; sometimes cres- 
centic in section. 
VII. 
E, nodes 
10-12. 
F (10 
nodes). 
As in VI, but with local 
internal phloem and 
sometimes endodermis 
in second cylinder. 
True leaf-gap constant ; 
dorsal half of second 
cylinder often fills gap 
caused by departure of 
trace (diagram). 
Horseshoe-shaped in 
cross-section. 
