740 Boodle. — Anatomy of the Gleickeniaceae . 
others, so that continuity of tissue is of no value in this case 
for determining its morphological nature. Again, it seems 
probable that the phloem-fibres which accompany certain 
protoxylem-groups through the internode in G. pectinata 
have been formed by transformation of some of the parenchyma 
usually found in that position, and the same might apply 
to the island of sclerenchyma, which is, however, only continued 
for a short distance above the node. 
The morphologyof stelar structures must remain at present 
doubtful, but the Gleicheniaceae have afforded no evidence 
disproving the general position taken in the section on the 
stele in the paper on Schizaeaceae (Boodle, ’ 01 , p. 403). In 
that paper the author is sorry to find that he misquoted 
Mr. Gwynne-Vaughan, by stating (’01, p. 405) that he had 
applied the term phloeoterma to the endodermis, and takes 
this opportunity of offering him an apology. 
While not laying too much weight on the importance of 
structural differences, it may be said that the anatomy 
supports several points in Hooker and Baker’s classification 
of the Gleicheniaceae, e. g. the inclusion of G. moniliformis 
in Gleichenia , perhaps the separation of Platyzoma micro - 
phyllum , and the raising of G. pectinata to a distinct section 
of the genus. 
A discussion of the relation of the Gleicheniaceae to the 
Hymenophyllaceae and Schizaeaceae must be deferred, but 
it may be said here that anatomical characters rather point 
to Lygodium as being the most primitive type found within 
these three Orders, to the Gleicheniaceae standing higher 
and having been derived from some form resembling Lygodium , 
while the Hymenophyllaceae may well have been derived by 
specialization from some stock not far removed anatomically 
from the Gleicheniaceae. This agrees well with the positions 
assigned to these Orders on other grounds by Bower (’ 99 , 
P . 129). 
