1912] BERRY—NEOCALAMITES 179 
of a whorl are not dissimilar in size. A second possible difference 
is that the leaves appear free to the base. This is not positively 
ascertained, however, and is of slight importance at best, since 
there must have been a progressive change from free leaves to 
united sheaths and vice versa, when the group as a whole is con- 
sidered, and the two lines of variation may have been contempo- 
raneous within the phylum. 
There is also a suggestive resemblance between the present 
species and the forms from the homotaxial Rhaetic deposits of 
Tonkin described by ZEILLER (13, p. 132. pl. 35. figs. 2-7) as 
Annulariopsis inopinata, gen. et sp. nov. This remarkable form, 
while based upon rather incomplete material, shows whorls of 
16-24 lanceolate-spatulate, uninerved, free leaves, the main 
difference betwen it and Neocalamites Knowltoni being the uniform 
size of the leaves of the latter. In Annulariopsis each whorl 
shows short leaves on one side and long leaves on the opposite 
side, with a regular gradation between the two, the maximum being 
1oo per cent larger than the minimum. 
It appears, therefore, that as regards habit and superficial 
characters Neocalamites was closely allied to and undoubtedly 
descended from some paleozoic Calamite. On the other hand, 
it does not seem to be genetically related to Schizoneura, although 
it comes after it in time. 
Neocalamites Knowltoni was a large plant, and it is quite possible 
that some of the fragments of large stems ro or 12 cm. in diameter, 
which are so abundant at some horizons in the coal-field, may repre- 
sent the main axis. The axis of the specimen, with its leaf-bearing 
subordinate branches, is interpreted as a lateral branch which was 
distinctly bifacial in habit. The material from the Triassic is 
too limited for certainty on this point, but it seems difficult to 
account for the uniform orientation of the numerous whorls of 
leaves on the distichous branches by appealing to compression 
during fossilization, which it would seem reasonable to suppose 
on even a single specimen would flatten some leaves in one direc- 
tion and some in another and would break off or bend some of 
the leaves. 
The obliquity of the plane of the verticils in Annularia is often 
insisted upon in the diagnosis of this paleozoic type, although some 
