3 72 Hickling . — The Anatomy of Palaeostachya vera . 
As mentioned in the description accompanying the section, the 
evidence that the sporangiophores were superposed on the bracts, and the 
members of the successive whorls also superposed, is insufficient (see p. 375). 
The Axis. The interest of this structure centres mainly in its very 
typical Calamitean anatomy. It alone causes Palaeostachya to be un- 
disputed as the cone of a Calamite. A transverse section of the peduncle 
is not to be distinguished from a young vegetative shoot, while a similar 
internodal section through the fertile portion differs only in the slight 
Fig. 2. Slightly oblique internodal transverse section. R. 31 *9^ dia. Plane of section ascends 
from right to left. This section has sporangia more complete than any other, and in conjunction 
with Text-Fig. 1 will give a fairly complete idea of the cone. It should be remembered that the soft 
cortex is completely removed. Br. = bract ; Sp. = sporangiophore ; O.S. — outer sporangium ; 
I.S. = inner sporangium ; S.Sct. = sub-epidermal sclerenchyma ; Ptxy.C. — protoxylem canal. 
‘pairing’ of the bundles. Two further peculiarities distinguish this axis 
from the vegetative stem ; there were no nodal diaphragms across the 
medullary cavity, while these were functionally replaced by nodal rings of 
sclerized cortex — the ‘ nodal discs ’ of Williamson. 
Cortex. No section shows this completely preserved, and only one 
shows fragments (Fig. 11). In this it appears to extend over about 
a quarter of the radius of the complete axis. It is a simple, large-celled, 
parenchymatous cortex, with its largest elements towards the exterior. 
On the outside of the xylem-bundles, groups of smaller elements may be 
traced, which no doubt represent the phloem (Fig. 8, phi). The 
epidermis is preserved only in a section through the insertion of a sporangio- 
