A ffinities of Per cinema and Diacalpe. 251 
condition of the pinna-trace is that of a miniature petiole-trace, except that 
only two, instead of four or more, subsidiary strands are present. From the 
prosrachial strands the pinnules are supplied, as were the pinnae from the 
adaxial strands of the petiole (Fig. 7, IX, x). Through the rachis of the 
frond from the departure of the first pair of pinnae to the departure of the 
second pair there run five vascular strands and a commissural strand. To 
the second pair of pinnae the supply is given off from the prosrachial 
bundles in the same fashion as to the first pair of pinnae. The same process 
is repeated for the third pair of pinnae. Between pair 3 and pair 4 the 
number of strands is reduced to three, with a commissural strand. And 
pair 4 (pinnae VII and Vlll) are given off again in the normal manner. 
Beyond pair 4 the vascular strands are only three in number with occasional 
fusions of the median aporachial strand and one or other of the prosrachial 
strands. Towards the tip of the leaf the strands are reduced in number to 
two, the pinna-supply going off in the normal fashion. Ultimately only 
a single strand remains in the rachis. This strand has a narrow plate 
of xylem, with no incurved ends, and from its edges the simple strands to 
the ultimate segments are quite simply nipped off. Here the plate extends 
in the direction towards the pinna to be supplied, and the marginal group 
of tracheides surrounds itself with phloem, pericycle, and endodermis, while 
the parent strand re-forms its simple plate. As this type of pinna-supply 
differs from that given to the basal pinnae, it is proposed to term it the 
c marginal J type, while that found in connexion with the lower pinnae and 
already described may be termed the c extramarginal ’ type. To these two 
types of pinna-supply and their significance reference will be made later on 
in the paper. 
The root is diarch, with a single plate of xylem, composed of a set of 
four or six tracheides and two protoxylem groups, one at either end. The 
protoxylem elements abut directly on the pericycle, which is of two layers 
of cells at these points. Between the secondary xylem and the phloem is 
a series of parenchymatous cells, one or two layers thick. These have 
prominent nuclei and dense protoplasmic contents. Phloem surrounds this 
zone on the outer side. The endodermis has brownish cells, while the 
cortex is made up of thickened cells with deep brown coloured walls. The 
greater part of the piliferous layer breaks away, leaving the cortex as the 
outermost layer of the root. The stele comes off obliquely from the back of 
one of the meristeles of the stock, the root passing out into the soil in 
a slightly decurrent direction. 
On the petiole and rachis of the mature leaf are innumerable paleae 
and hairs. The paleae are very similar to those on the stock, but their 
edges are quite entire. Each runs out into an acuminate apex (Fig. 8). 
Along the margins of a palea a few unicellular glands are inserted (cf. the 
paleae of Blechmim Occident ale , Gardiner and I to, ’87), and these project 
