Anatomy of Solenostelic Ferns . 699 
cular system. The leaf-trace consists of a single curved 
strand inserted so that its concavity faces the median 
dorsiventral plane of the rhizome, and the leaf-gap closes 
up at the same time as the acroscopic flange of the leaf-trace 
departs. The enlargement of the leaf-gap margin is so pro- 
nounced that it projects markedly towards the interior, and, 
what is more important, this projection is not confined to the 
limits of the open leaf-gap, as in the previous examples, but is 
continued as a ridge upon the internal surface of the soleno- 
stele throughout the whole length of the internode, running 
from one leaf-gap margin to the other (Fig. 11). In the 
immediate neighbourhood of the leaf-gap the additional 
xylem-elements that cause the internal projection of the 
margin are in more or less complete continuity with the rest 
of the xylem-ring, just as in Dicksonia apiifolia , &c., but 
in the internodes they become separated off as a distinct 
strand (Fig. 12), which may even be surrounded by a phloem- 
ring of its own distinct from that of the solenostele. This 
separate strand of xylem generally attains its greatest inde- 
pendence in the upper part of the internode, and is most 
closely fused with the xylem-ring of the solenostele towards 
the top of the leaf-gap. In my specimens the separate strand 
of xylem never became free from the endodermis and peri- 
cycle of the solenostele, but in a stout example it seems 
probable that along part of its course it may become com- 
pletely isolated in the central parenchyma. The protoxylem- 
elements of the solenostele are located in definite endarch or 
mesarch strands ; a similar protoxylem-group is sometimes 
to be found in the internal xylem-strand (Fig. 12). 
The insertion of the leaf-trace in this Fern is further com- 
plicated by the presence of lateral shoots and of one or two 
small vascular strands which run across the leaf-gap very 
much in the same way as those already described in Hypolepis. 
In this case they start from the internal surface, or from the 
basiscopic margin of the leaf-trace (Fig. 11), and run forwards 
to the free margin of the leaf-gap. The marginal thickening 
and the transverse strands were found at nearly all the leaf- 
