26 Lady Isabel Browne. 
four times pinnate (4); but in B. simplex it is unbranched. In 
Helminthostachys the compound frond bears an irregularly branched 
adaxial spike. Those who, like Professor Bower (4) and Mr. 
Worsdell (45), homologize the spike with the Lycopod sporangium, 
and the subtending lamina with the sporophyll, naturally regard the 
simpler forms as primitive. Professor Bower, in his later publications 
admits the filicinean affinities of the gametophyte and makes of the 
order a phylum intermediate between the Ferns and the other 
Pteridophyta. Reasons for the inclusion of the Adder’s Tongues in 
the ferns will be given in discussing the affinities of the phyla. 
Those who agree with Dr. Campbell that the spike represents the 
sporogonium of the Bryophyta, will probably also agree with him in 
regarding Ophioglossum simplex as the most primitive species, for in 
some cases at least it seems to possess a terminal spike devoid of a 
lamina (8), though in others a small blade is present (10). Dr. 
Campbell regards this species as the most primitive Pteridophyte, 
looking upon its spike as terminal and as representing a sporogonium, 
and its other organs as outgrowths from the spike (15), (13). The 
numerous and grave objections to such a view are bound up with 
the question of the origin of the Pteridophyta and lie outside the 
scope of this article. The fact that the sterile leaf of O. pendulum 
has no adaxial bundles, such as are found in the fertile leaf, even at 
the base of the petiole is, as Dr. Campbell claims, a strong reason 
for supposing that the spike, when present, really extends to the 
base of the petiole. But this does not prove the spike to be terminal 
and the lamina a lateral outgrowth from it; for it seems more 
natural to regard spike and lamina as branches of the frond. Dr. 
Campbell practically admits this alternative, for he says that if the 
spike be not regarded as terminal and the lamina as lateral it would 
seem natural to return to Mettenius’ view that the leaf is divided 
into equal branches (15), The view that the spikes represent 
branches of the frond, though not always necessarily primary or 
equal branches, seems the most natural one. It is supported by the 
course of the vascular bundles of the fertile leaf of O. pendidum and 
of the complex O. palmatum (9), by the pinnation of the spike of 
Botrychium and its irregular branching in Helminthostachys, and by 
the termination of the sporangiferous projections of the spike of this 
genus as laminar expansions beyond the sporangia; these projections 
—the so-called sporangiophores—would then represent pinnules. 
The forms in which a simple leaf bears a single spike would then be 
reduced, while the abnormal specimens of Ophioglossinn vulgatum s 
figured by Professor Bower, would be reversions instead of progressive 
