32 Johnstone: Coal Measure Plant Records. 
The periodic recurrence of short and long internodes seems. 
to be restricted to the Calamitina, with their ringed arrange- 
ment of small branches. I have found no examples, figured 
or in specimens, among the Eucalamites or the Stylo-calamites. 
Williamson (1), Stur (2), Kidston (3), and Horwood (4), 
have figured and described this grouping of internodes. 
Williamson says it may have some specific meaning ; Stur-and 
Kidston do not discuss it ; Horwood considers that the short 
internodes furnish support to the whorls of branches. 
Before trying to clear up the functional point, it is necessary 
to decide which is the upper region of the fossil. The evid- 
ence is of two kinds. In the first place, there is a line of what 
are pretty certainly leaf-scars subtending each branch node, 
whilst certain details in the branch scars themselves can be 
identified with parts proved in structural specimens to be the 
upper portions of the branches. Secondly, there is complete 
similarity with other branching stems, about which there is no 
doubt as to the interpretation. In many of Stur’s figures the 
relative positions of leaves and branches are plainly evident, 
and the branches bearing the whorls of leaf-scars are still in 
connection with an older axis. Inall cases the internode below 
the branches is relatively long. 
It seems clear that in some species of Calamites, a recurrent 
cycle of internodes was correlated with the occurrence of whorls. 
of branches, and that immediately above the branch node 
there appeared one or more stunted internodes. This can 
hardly be regarded an arrangement to furnish special support 
for the branches, as Mr. Horwood suggests. It is more pro- 
bable that it was a condition of growth determined by the 
presence of the numerous branches ; the diversion of a large 
amount of food material outwards to these secondary members. 
might lead to an imperfect supply being furnished to the main 
axis just above them. 
REFERENCES. 
(1) Williamson, W. C. (1871). ‘On the Organisation of the Fossil 
Plants of the Coal Measures.’ Phil. Trans., vol., 161, page 495, plate 27, 
fig., 30. 
(2) Stur, D. (1887). ‘Die Carbon-flora der Schatzlarer Schichten, 
Abt II., Die Calamarien.’ Abhand K. K. Geol. Reichsaust, Wein, 
Bal, Xi, Abt 2. 
(3) Kidston, R. (1889). ‘ Fossil Plants in Ravenhead Collection.’ 
Trans. Roy. Soc., Edin., vol. 35, No. 10, plate I, fig. 1. 
Kidston, R. (1908). ‘Les Vegetaux houillers du Hainault Belge.’ 
Mem. Mus. Roy. Hist. Nat. Belg., T. 1V., plate XIII., fig. 1. 
(4) Horwood, A. R. (1910), ‘On Calamites Schiitzei, Stu... Journ. 
Linn. Soc., vol. 39, page 279. 
sO 
A paper on ‘ The Equipment of a Yorkshire Quarry ’ (Craven district), 
by R. Parker, appears in ‘ The Quarry ’ for December. 
_N aturalist 
