of the Rocks associated with the Coal of Australia. 155 



the above-mentioned Phyllotheca. But a still more interesting 

 and important proof of the relation of those plants to Casuarina, 

 and removing them still farther from Equisetum, 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 (see PI. XI. fig. 1) with the 

 joints more approximate 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 Cambridge 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 Phyllo- 

 theca australis is described as having the sheaths closely applied 

 to the stem, the leafy appendages twice the length of the sheaths, 

 without midribs, and having the naked portion of the stem be- 

 tween 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 characterize 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 

 cannot do better than as I have proposed. I may then briefly 

 characterize the genus and species as follows : — 



Phyllotheca. 



Gen. Char. Stem slender, jointed, simple or branched ; branches 



springing from above the joints, not arranged in the same 



plane ; surface smooth or longitudinally sulcated ; articulations 



surrounded by sheaths, the free edge of which terminates 



