256 BOTANICAL-GAZETTE locroBER — 
modern Calamites and in Equisetum. It follows that there could 
have been no foliar gaps in this genus, if the general anatomical 
conditions were like those found in the rest of the calamitean stock, 
as has already been indicated by the present writer in the memoir 
on Equisetum. Our knowledge of the cone of Archeocalamites is 
very incomplete and nothing is known of its anatomical structure. 
It may be stated with some confidence, if credence is to be attached 
to the doctrine of descent and to the general principles of modern plant 
anatomy, that the equisetal stock entirely lacks foliar gaps immediately 
above the outgoing leaf-traces. Dr. Scort’s statement that in respect 
to their vascylar anatomy the Equisetales “reach the level of the 
simpler gymnosperms or dicotyledons” (Progressus rei botamicae, 
p. 157) will apparently, as a consequence, need some revision. 
There further seems to be no reason to doubt that the Equisetales 
are quite typical Lycopsida in the sense defined in the writer’s two 
memoirs, and are as a-consequence far removed from any mere affinity 
with any of the pteropsid series. ; 
It may be added that there seems to be no reason at the present 
time, on anatomical grounds at any rate, to suppose that the Pterop- 
sida had a sphenophylloid or ophioglossaceous origin from the 
Lycopsida. Neither Pseudobornia, of the reproductive organs of 
which we know little and of the anatomical structure of which we 
are entirely ignorant, nor Ophioglossum, of which the characters 
anatomical and reproductive are entirely filicinean, can serve . 
phylogenetic link between the primitively small-leaved veritrisporan- 
giate (adaxial) forms (Lycopsida) and the palingenetically large-leaved 
dorsisporangiate (abaxial) forms (Pteropsida). As Professor bai 
LEY has recently put it in a review of Professor Bower's Origin of 4 
land flora,*° “on the general point of the relation of the ‘microphyll " 
the ‘megaphyll,’ there is no evidence of any capacity of the micto” 
phyll to evolve the megaphyll.” 
Summary 4 
1. True foliar gaps occur immediately above their corresponding 
leaf-traces and are not lateral to the leaf-traces. super 
2. Foliar gaps are absent in Phylloglossum, although os: 
© New Phytologist 7:125. 1908. 
