253 
Davie . — The Structure and 
an advanced dictyostele, but all the gaps are here, too, leaf-trace gaps. 
Schlumberger (‘ Flora ’, cii, N. F. 2, 1 9 1 1 , p. 409) states that there are perfora- 
tions in the dictyostele in Diacalpe aspidioides : ‘ Ausser den Blattlucken 
tritt wie bei den Cyatheaceen eine ganze Reihe von “ Perforationen ” auf.’ 
In the stocks I have dissected I have been unable to discover the presence 
of any such perforations. In all respects the dictyostele of Diacalpe has 
been found to agree with those of Peranema cyatheoides and N ephrodium 
filix-mas. The leaf-trace is made up of three main bundles and a varying 
number of subsidiary bundles, with occasional commissural bundles uniting 
one main bundle with the subsidiary ones or with one of the other main 
bundles. The strands of the leaf-trace are inserted on the lower half of 
each gap opposite the entrance of the petiole to which the trace belongs, 
and the median main bundle of the trace enters the dictyostele at the lower 
fork of the gap. With regard to the histology of the supply of the leaf- 
trace from the dictyostele, the facts are the same for Diacalpe aspidioides as 
for Peranema. The adaxial main bundles of the leaf-trace have deeply 
incurved hooks on their adaxial faces. From the backs of these hooks the 
pinna-traces gooff in the extramarginal fashion. The pinna-trace is at first 
a simple strand, but it soon breaks up, as in Peranema , into three strands. 
The pinnules are supplied from these on the extramarginal type. The 
ultimate pinna is supplied in marginal fashion from a dorsiventrally- 
constricted simple xylem-plate. The same process occurs in the supply of 
the ultimate pinnules from the pinna-traces. 
Scales of three rows of parenchymatous cells, some six or eight in each 
row. occur on the leaves, usually above a vein or veinlet. Simple unicellular 
glands, but no multicellular hairs bearing glands, occur sporadically on 
rachis and leaves. Paleae of the type found in Peranema , but without 
glands on the edges, are present at the bases of the primary pinnae and on 
the raches and petiole in younger leaves ; few or none are found on fully- 
matured leaves. 
The sorus is at first entirely covered by the indusium. There is in this 
indusium no such pit or pore at one side as is found in that of Peranema. 
Here the indusium forms an unbroken symmetrical covering for the spo- 
rangia, coriaceous in texture, with cells of polygonal outline possessing 
triangular thickenings at the corners. In section these cells are rectangular, 
often square, with thickened walls. 
The receptacle is short but not flattened, and is supplied by a short fan 
of tracheides from the vascular bundle of the veinlet on which the sorus is 
seated. The sporangia are numerous. They are of all ages in the same 
sorus and are inserted on the receptacle in distinctly mixed fashion. There 
is no trace of a basipetal sequence of development. The full developmental 
stages have unfortunately been unavailable, but even in moderately young 
sori no traces of very young sporangia were found at the basal edges of the 
