H 
Scott. — On the Fertile Shoots of 
The diameter of the vascular ring is about 2-5 mm. ; allowing for the small 
development of the wood, this is about the full size of the stele in the 
preceding sections. Evidently we are here approaching the apical region 
of the bud ; it is interesting to find that the vascular bundles are at first 
widely separated, and that it is only at a later stage that they become 
united into a more or less continuous vascular zone. 
About nine seeds of Mitrospermum occur in the series, some of which 
are evidently young. In section 3019 three of the seeds closely surround 
the shoot and all appear young, the cell-walls of the sclerotesta being but 
little thickened. In one of them the indications of youth are especially 
marked ; all the cell-walls are remarkably thin, the megaspore is relatively 
small, and there appears to be a thick layer of nucellar tissue persisting 
between the megaspore and the integument. 
Discussion . 
There can, I think, be no doubt that the two specimens just described 
are of the same kind. Both are of the nature of buds or apical shoots, 
as is proved by the leaves wrapped closely round the axis. They agree 
in the structure of the wood, in the single leaf-traces dividing in the cortex, 
and in the massive leaf-bases. The chief differences are, first, in the 
structure of the pith, which seems to have been discoid in the first specimen 
and continuous in the second. There is a slight difference also in the form 
of the pith, which is markedly pentagonal, at least where it attains its full 
size, in the second specimen, and only faintly angular in the first. This, 
however, is a small point. 
Another conspicuous difference is the striking contraction of the whole 
shoot and its stele towards the base in the second specimen, while the 
diameter is fairly uniform throughout in the first. This distinction suggests 
that the second specimen may have been, a lateral bud, and the first a 
terminal one. This suggestion might perhaps also throw some light on the 
difference in the structure of the pith. 
The anatomical habit of both shoots is distinctly that of a Mesoxylon ; 
the presence of centripetal wood and the polydesmic structure of the 
encircling leaves show that the affinity is a real one. But in the important 
character of the single leaf-trace there is a marked distinction from 
Mesoxylon , for in all the species referred to this genus the trace is double 
where it passes through the wood. This, in fact, has been made a character 
of the genus (Scott and Maslen, 1910 , p. 2 37). It is true that in the buds 
of the fertile shoot of M. multirame the leaf-trace is single, but here the 
reason is obvious, for it supplies a monodesmic bract. In the shoots now 
under consideration the leaf-base and leaf have many bundles, and yet the 
trace is single at its origin, only dividing as it passes through the cortex. 
This peculiar feature might no doubt be due to the shoots being of a special 
