Affinities of Helmiut ko s tacky s zeylanica. 427 
closely approaches the Ophioglosseae than any of the other 
groups of Ferns ; and although it in some respects resembles 
some of the Lycopods, especially certain Selaginellas, it 
differs from them inasmuch as the gap in front of the trace 
is a foliar and not a ramular one as in all those Selaginellas 
concerning which we have been able to obtain information 1 . 
For a short interval behind the place of exit of each leaf-trace, 
the gap of the preceding one has closed up, and hence a 
section of the stele in this region exhibits the form of a 
complete ring of vascular tissue enclosing a central strand 
of parenchyma. 
When the foliar stele has traversed the cortex of the 
rhizome and passes up towards the base of the leaf, it divides 
rapidly into about seven or eight (sometimes however fewer) 
bundles by a series of dichotomous branchings. These run 
up into the petiole of the leaf and form the ring of bundles 
which are situated near its periphery. There is some anasto- 
mosis between them as they continue their course through 
the leaf-stalk up to the level where the leaf branches. Just 
below this spot a very complex series of anastomoses ac- 
companied by a redistribution of the bundles occurs which 
results in a tolerably regular vascular supply being given off 
to each branch of the leaf. There are three of these branches 
in a sterile, and an additional adaxial sporangifervus one in a 
fertile, leaf. Each midrib of the three vegetative leaf-branches 
receives typically four bundles, of which the two outer are 
the stronger. These soon break up again, and it appeared 
useless to attempt to trace them further. The fertile leaf 
segment also receives four (or five) bundles, but these are 
clearly separated from the strands of the barren segments 
at some little distance from the point of branching, though at 
this spot there are again cross-connexions visible between 
the various bundles. The transverse sections figured in 
FI. XXI. Figs. 7, 8, 8 a, will serve to convey a general idea 
of the distribution of the vascular strands in this region. 
1 See Harvey Gibson, Contributions towards a knowledge of the Anatomy of 
the Genus Selaginella, Annals of Botany, vol. viii. 
