59 
Inter-relationships of the Phyla. 
constancy he is inclined to attribute considerable weight as a 
morphological character to the median position of the sporangium 
on the adaxial surface of the sporophyll in the Lycopods (6), for in 
discussing the position of the sporangium in Selaginella he wrote as 
follows : “ The mere fact that there is variety within the genus in 
this much discussed and greatly overrated character, should show 
sufficiently that, however interesting its morphological bearings 
may be, it is not a point of much systematic importance ” (5). 
Further, in asserting the non-foliar character of the Equisetaceous 
sporangiophore, Professor Bower has pointed out that similarity of 
position is no proof of homology, quoting as examples prickles and 
leaves, both arising from similar tissues of the axis (5). The 
similarity of form, admitted not to be so obvious, seems very slight; 
in Professor Bower’s figure of the sporangium of Lycopodium 
carinatum, it is enhanced by the shading of the extremities only of 
the sporogenous mass (6). This shading gives a fallacious appearance 
of two sporogenous masses, somewhat separated from one another 
as are the sporangia of Ophioglossum. As pointed out in the 
preceding article the frequent pinnation of the Ophioglossaceous 
spike and the presence of laminar expansions beyond the sporangia 
in Helminthostachys are evidence of the frond-like nature of the 
spike. Professor Bower regards the sporangiferous projections of 
Helminthostachys as outgrowths, through which vascular bundles 
run to the bases of the former loculi of a septate sporangium. No 
such character as the approach of the vascular bundle to the base 
of the sporangium is characteristic of the Lycopods and this view 
seems terribly strained. Again, the similarity of the development 
of Lycopod sporangium and Ophioglossaceous spike is not very 
close. 
It has already been pointed out, in dealing with the affinities 
of the Lycopods, that in spite of its radial symmetry, the gameto- 
phyte of the Ophioglossaceae is probably not closely related to 
that of the Club-Mosses. As Dr. Lang notes the antheridia are 
essentially of the same type in all Pteridophyta (26); but the 
presence of a basal cell in the archegonium recalls the Marattiaceae 
rather than the Lycopods (12). As regards the similarity of 
embryology of the Ophioglossaceas the first result of germination, 
after the division into octants, is a cell mass in which the primordia 
of stem and cotyledon are not distinct (11), (6). This makes an 
accurate comparison of their embryology with that of the Lycopods 
difficult, but the absence of a suspensor and the early development 
