70 ON THE FOSSIL FLORA OF THE COAL DEPOSITS OF AUSTRALIA, 



Equisetum. — Sheath undivided, terminating in short adpressed 

 teeth. 



Phyllotheca. — Sheath terminating in long linear narrow teeth, 

 diverging from the stem in whorls. 



Brongniart in his definition, speaks of them as simple straight 

 articulate stems, surrounded at regular intervals by sheaths applied 

 to the stem as in Equisetum, but terminating in long thread-like 

 leaves, which replace the short teeth of the Horsetails. These 

 leaves are erect, or more often spread out horizontally, or even 

 reflected. The leaves are linear, acute, without any distinct 

 neuration, and at least, twice as long as the sheath. The sheaths 

 themselves show faint longitudinal grooves which disappear 

 towards the base, and which seem to correspond to the intervals 

 between the leaves, as the grooves on the sheaths of Equisetum 

 correspond to the intervals between the teeth. The stem in the 

 space, which separates the teeth, appears smooth, but on the 

 fragments of larger ones which probably belonged to older 

 individuals of the same plant, there are regular striae, almost 

 like those seen on Calamites. 



In Lindley and Hutton's Fossil Flora (Vol. II., p. 89) the 

 following passage occurs :— " A little known plant called Phyllo- 

 theca australis, found in che coal of New South Wales, is described 

 by M. A. Brongniart as consisting of simple, straight, articulated 

 stems, surrounded at intervals with sheaths pressed close to the 

 stem, as in Equisetum, but terminated by long linear leaves, which 

 stand in the place of the short teeth of the sheath of Equisetum. We 

 have ascertained from the examination of specimens communicated 

 by Prof. Buckland, that in some respects M. Brongniart's description 

 of Phyllotheca is inaccurate, and that the leaves instead of spring- 

 ing from the edge of a sheath arise immediately from the stem, as 

 in the fossil under consideration (Hiiipurites gigantea), so that the 

 two would appear to be nearly allied. But in addition to the 

 whorl of distinct leaves, in Phyllotheca there is a sheath originating 

 within them, and closely embracing the stem, to which it gives 

 the appearance of the barren shoot of an Equisetum, with its 

 whorls of slender branches on the outside of a toothed sheath." 



