Affinities of Helminthostachys zeylanica . 443 
9. The apex of both stem and root is provided with an 
apical cell, but the sequence of segmentation very early 
becomes unrecognizable. 
10. The vascular strand of the root varies from tetrarch to 
heptarch. 
11. The root branches monopodially : but as a rule the 
lateral roots are abortive, or at any rate do not commonly 
persist. 
In reviewing the observations contained in this paper, with 
the object of attempting to determine the nearest affinities of 
Helminthostachys , we find that they by no means point in one 
direction only. This is partly due to the difficulty of establish- 
ing a criterion of value which will enable the weight of any 
given facts to be duly estimated ; but it is also partly due 
to the fact that the plant itself has leanings towards different 
groups of plants. 
Without going so far as to regard Helminthostachys as 
constituting in any way a link between the Ophioglosseae 
and the Lycopodineae, it can hardly be disputed that whilst 
in most important respects it is clearly nearly related to the 
former, it nevertheless in some of its salient peculiarities 
recalls the generalized type of Lycopodinous structure. 
Thus in the character of the stele, whilst it resembles in 
a measure that of both Botrychium and Ophioglossium Bcr - 
gianum , it cannot be doubted that the resemblance with that 
of Phylloglossum is more obvious still, in spite of the absence 
from it of intercellular spaces in the xylem which occur in 
the last-named plant. Again, the structure of the root-stele 
recalls that of some Lycopods far more than it does those 
of either of the other genera of the Ophioglosseae. But on 
the other hand, the evidence for intimate and real relation- 
ship with the Ophioglosseae is of a much stronger order, 
as might from the general habit of the plant have been antici- 
pated. In the consistency, texture, and appearance of the 
stem and roots (apart from the dorsiventrality of the former), 
it irresistibly recalls Botrychium and Ophioglossu m . Again, 
in the mode of formation of the stipules it strongly resembles 
