238 Lady Isabel Browne. 
should expect the remains of internal endodermis to be always near 
the xylem ring. Against this it may be urged that an obsolescent 
and functionless structure might well tend to be irregular in position ; 
but it must be admitted that it is difficult to account for the internal 
tracheides if the ancestors of Schizcea malaccana possessed a 
complete internal endodermis shutting off the pith from the vascular 
tissues. 
Mr. Boodle also holds that endodermal pockets are not 
necessarily vestigial, and that they might arise for mechanical 
reasons. But he regards them as vestigial in Schizcea dichotoma, 
examined by him, because he thinks it hard to explain the utility of 
the isolated endodermis. He admits that the impossibility of 
discovering a function in any structure is an inconclusive reason for 
regarding that structure as vestigial, but maintains that the 
supposition of its being functionless is supported by its haphazard 
occurrence. He proceeds to compare Schizcea with Aneimia. A. 
mexicana is solenostelic ; its external and internal endodermes are 
continuous through the leaf-gaps, while the smaller A. coriacea, 
closely resembling A. mexicana, also has an internal endodermis, 
but the endodermal pockets are independent of the latter. Mr. 
Boodle naturally concludes that these pockets of A. coriacea are the 
reduced remains of previous connections between outer and inner 
endodermes. As both these features occur locally in Schizcea 
dichotoma, Mr. Boodle considers that this suggests the view that 
outer and inner endodermes were once, in the phylogeny, continuous 
through the leaf-gaps, and that the stele of Schizcea is therefore a 
reduced ectophloic siphonostele ; for he points out that there is no 
reason to suppose that the ancestors of Schizcea ever possessed 
internal phloem (6). Dr. Jeffrey, nevertheless, regards the stele of 
Schizcea as probably “ derived by reduction from that which is 
characteristic of Moliria and Aneimia ” (20). This view is based on 
an analogy with certain conclusions drawn from Dr. Jeffrey’s study 
of the Osmundacese. Though there is a good deal to be said in 
favour of these conclusions, they are not generally accepted even 
for the Osmundacese, and there seems little reason to apply the 
analogy to Schizcea ; for though the presence of vestigial internal 
phloem would not necessarily indicate reduction from the dictyo- 
stelic type of Mohria rather than from solenostely, yet its absence 
in Schizcea is a strong argument against reduction from either of 
these types. 
To recapitulate : It seems to be generally agreed that the 
