The Coal of Australia. 
441 
and removing them still farther from Equiselum, is to be found 
in their mode of inflorescence, of which I have fortunately noticed 
a fragment among the specimens at my disposal. The specimen 
alluded to is a portion of a branch, with the joints more approxi¬ 
mate than on other parts of the plant, their length being scarcely 
equal to their diameter; the sheaths are the exact length of the 
internodes, and fringed on their upper margin with a dense little 
whorl of (I think two-celled) anthers, agreeing very closely with 
the male flowers of Casuarina stricta and allied species, with 
which (being in flower at this time in the houses of the Cam¬ 
bridge Botanic Garden) I have been enabled to compare it as 
advantageously as the state of preservation of the fossil would 
allow. The fructification of Equisetum is entirely different, 
forming a dilated, club-shaped mass at the end of the branches 
or at the extremity of a particular stem. The Phyllotheca 
australis is described as having the sheaths closely applied, to the 
stem, the leafy appendages twice the length of the sheaths, with¬ 
out midribs, and having the naked portion of the stem between 
the sheaths smooth. Of the two species which I have seen this 
would best agree with the branched one, which however has a 
midrib, although not a very prominent one. The species 
which agrees with the definition in being simple-stemmed, differs 
in having the sheaths very loose or infundibuliform, and so long 
as to extend the entire way from one joint to the next, so as to 
leave no bare space of the stem visible; the leaves are very long 
and have a strong prominent midrib, and the stem when deprived 
of the sheaths is seen to be always coarsely sulcated. Under 
these circumstances the obvious course seems to be to modify the 
definition of the genus so as to include the two species under 
consideration, and to characterise them as distinct species. If 
the supposed affinity with Equisetum were borne out, I should 
probably have considered the loose-sheathed, simple-stemmed 
plant as the fertile shoot, and the branched stems with small 
tight sheaths as the barren shoots, following the analogy of some 
of our best-known recent species of Equisetum ; but having seen 
that they are constructed in an essentially different manner, we 
