366 Boodle. — Anatomy of the Schizaeaceae . 
L. japonicum , agreed with what Bower (’ 89 , p. 322) found 
in L. scandens , i. e. it had a three-sided apical cell, and a com- 
paratively flat apical cone. 
Lygodium, petiole and node. 
A transverse section of the petiole of L. japonicum is 
represented in Fig. 4. The xylem, which forms a solid mass 
at the centre of the bundle, has the same characters as in the 
rhizome, that is, it consists chiefly of large scalariform 
tracheides and chains of parenchymatous cells. It has three 
prominences, one median and two lateral, where the first 
formed tracheides occur. On the morphologically lower side 
(the upper side in Fig. 4) the prominence bears a pair of 
protoxylem-groups composed of spiral tracheides. Each of 
the two remaining prominences has one or two spiral 
tracheides connected with it, but most of the small peripheral 
tracheides in this region are scalariform. The protophloem 
forms a scarcely broken ring round the xylem, and the meta- 
phloem attains its greatest thickness and includes its largest 
sieve-tubes in the three bays alternating with the three 
prominences of the xylem ; the lateral bays being here 
considerably deeper than the median one. The pericycle 
is mostly from one to two cells thick. The endodermis is 
small-celled, and its cells contain a mucilaginous substance. 
The form of the xylem in transverse section varies according 
to the distance from the base of the petiole. Close to the 
base the xylem becomes much more rounded, while higher 
up in the petiole the prominences of the xylem become more 
and more pronounced. Some details on this point are 
given below under L. dichotomum. One or two granular 
bodies, probably siliceous, were observed in the petiole of 
L. japonicum. 
In the petiole of L. dichotomum the structure is of the same 
type as in L. japonicum in the corresponding region, and the 
shape of the xylem-mass undergoes similar changes according 
to the level. Quite at the base of the petiole the xylem has 
an oval outline ; at some little distance from the base (e. g. at 
