378 Hickling. — The Anatomy of Palaeostachya vera. 
tissue generally preserved is the sclerenchyma, which extended as a broad 
band under the ventral surface, and occupying about two-thirds of the 
width of the bract (Fig. 15, set.). The figure just referred to shows the 
lozenge-shaped form of the complete bract. The section is probably from 
about the middle of the ascending portion. The epidermis is well marked. 
Towards the dorsal side palisade-tissue is distinctly indicated. The 
single median bundle, which is evident projecting from the sclerenchyma 
into the adjacent soft tissue, retained this relative position throughout the 
bract. Usually, it has vanished along with the soft tissue. Its vessels were 
spiral and annular. The general form and extent of the parenchyma in the 
horizontal part of the bract is indicated in the diagram Text-Fig. 1. The 
thickness of the entire bract is there under-, rather than over-estimated. 
The Sporangiophores. In an external view these organs must have 
appeared to be practically in the axils of the bracts, though as will be 
realized from an examination of the oblique nodal section, Fig. 7, they did 
not become completely free for a short distance above the insertion of the 
bract. 
The sporangiophore itself was very similar to the typical form found 
in Calamostctchys. The stalk was straight, and in a transverse section 
generally showing the form of a square with rounded angles, and with its 
diagonals placed radially and tangentially — a form obviously due to the 
pressure of the four sporangia which surrounded it. The structure of the 
stalk is very imperfectly preserved. Fig. 5 ( sp . tr.) shows the median 
vascular bundle fairly well, while a few sections show very imperfect traces 
of it nearer the distal end. All efforts to determine its orientation have 
been unavailing. Surrounding the bundle is a regular mass of tissue, of 
more or less longitudinally elongated elements, bounded by a simple 
epidermis. In this tissue I have not been able to trace the phloem. 
A considerable portion of this ground-tissue consists of the elongated 
dense black elements which have been referred to above (p. 376). Usually, 
nearly all the cells between the bundle and the sub-epidermal layer on the 
outer side of the stalk are of this type, while there are commonly some on 
the inner side as well. They may be symmetrically disposed round the 
bundle, or even mainly on the inner side. 
The peltate head is preserved only in fragments. The most nearly 
complete example is that of Fig. 4. The mushroom-like form is well 
shown, and the thick black external covering of long palisade-cells. The 
space below this was doubtless (from analogy) occupied by soft parenchyma 
in which the stalk bundle divided into four branches, one for each sporan- 
gium. There is evidence that the outline of the head was undulating, as 
indicated in Text-Fig. 1. 
The Sporangia. As already indicated, each of the sporangiophores 
had four sporangia round it, so that there were normally seventy-two 
