440 
The Coal of Australia. 
pendent whorl of leaves outside of the base of the sheath, as de¬ 
scribed in the ‘ Fossil Flora.’ This double arrangement would 
be so anomalous, that it is the more important to have the means 
of ascertaining the true relation of those parts in accordance with 
Brongniart’s original view. 
Brongniart describes the stem as smooth, and I find the spe¬ 
cimens before me apparently divisible into two groups, one 
having the stem smooth, the other having it coarsely sulcated 
longitudinally, as in Calamites. All the botanists alluded to 
agree in describing the stem Phyllotheca australis as simple;—. 
all the sulcated stems I have seen are simple, but a number of the 
smooth or slightly striated stems are distinctly branched, and in 
a manner quite distinct from Equisetum. In Equisetum, if we view 
with most botanists the sheaths as produced by the mere lateral 
union of the leaves, and thus representing the foliage of other 
plants, we have the extraordinary character of the branches arising, 
not as axillary buds originating immediately above and within the 
base of the leaves, but originating below the joints and external to 
the sheaths. This is not the case with the fossil before us, in which 
the branches originate directly over the joints, and are therefore 
within and axillary to the sheaths, which may thus, with their 
appendages, be considered as true leaves, and having the same 
relation to the branches as in ordinary plants. This character 
is of such importance, that the resemblance of Phyllotheca to 
Equisetum is proved by it to be of the most trifling nature, and 
that there can be no real affinity between them. On the other 
hand, when compared with Casuarina, the affinity seems to me 
to be exceedingly strong, although botanists have not, I believe, 
hitherto so considered it. The Casuarmce are exogenous weeping 
trees, with slender cylindrical branches, their shoots regularly 
jointed, longitudinally sulcated, and surrounded at the joints with 
toothed sheaths as in Equisetum ; while the branches originate 
either in a verticillate or irregular manner immediately above the 
joints and within the sheaths, showing a perfect agreement with 
the above-mentioned Phyllotheca. But a still more interesting 
and important proof of the relation of those plants to Casuarina, 
