382 Hickling . — The Anatomy of Palaeostachya vera . 
sporangiophores represent independent whorls. I feel convinced that it 
will be found that the sporangiophore traces really arise just above the 
bract-traces, and then rise in contact with their parent-bundles till they turn 
out into the appendages to which they belong. If this view is correct, then 
the only important differences between Calamostachys and Palaeostachya 
are the absence of any considerable reflection of the sporangiophore-trace 
in the former, and the possession of (approximately) two bracts to each 
sporangiophore. I do not think that much stress should be laid on either 
of these differences. Among various Calamite cones the sporangiophore 
may be found attached to almost every part of the internode. The number 
of bracts in the whorl appears to have been anything from that of the 
sporangiophores up to three or more times as great as the latter. 1 It is 
noteworthy that although the specimens of Calamostachys with structure 
preserved have approximately two bracts to each sporangiophore, the 
relation is seldom exactly two to one, while in Palaeostachya it is possible, 
that the number of bracts somewhat exceeded that of the sporangiophores. 
A tendency to multiply the number of appendages in each whorl seems to 
have been a characteristic Calamarian feature. Hence I would conclude 
that Calamostachys and Palaeostachya need not be remotely separated. 
An interesting suggestion as to a possible explanation of the course of 
the sporangiophore trace in Palaeostachya was made to me by Mr. Boodle, 
to the effect that the triangle of sclerenchyma which is seen in longitudinal 
section between the ascending and descending limbs of the trace may be 
an upgrowth of the sclerized tissue of the disc, which has carried the trace 
with it. Against this view, however, I would urge the following con- 
siderations : Firstly, in CalamodendrostacJiys there is already a real, though 
small, reflection of the trace, while no sclerized tissue is present. Then the 
tissue referred to appears to me to be associated with the trace itself more 
intimately than with the disc. I have pointed out (p. 378) that in the 
sporangiophore-stalk there is a mass of dense resistent tissue which com- 
pletely or partially surrounds the bundle, and that is a continuation of the 
strand of similar tissue which lies under the bundle in the ‘ disc.’ No 
section exists good enough to show clearly the nature of the triangle of 
‘ sclerenchyma * referred to above, but I strongly suspect that it consists, 
in part at least, of that same strand of tissue following the bundle and 
reflected with it. I think Fig. 21 accords with this view as well as can be 
expected. Finally, the only explanation of such an upgrowth would be 
a mechanical one, and I should doubt if any appreciable gain in rigidity 
is obtained in this way, though I would not profess to understand the 
remarkable mechanical adaptations of this cone. In view of all the facts 
at present available, the phylogenetic explanation seems to me much more 
probable, though even if the alternative view should prove correct, the 
1 Weiss, ’76, Taf. xvi, Fig. 3 B, Calamostachys germanica. 
