Affinities of Helminthostachys zeylanica. 439 
Still the general endarch tendency in the leaf-bundles is very 
obvious. 
The xylem and phloem of the two bundles, which are still 
united into one strand, are seen to become still more divided 
up by parenchyma which runs, roughly speaking, in the radial 
direction across them, and thus paves the way for the sudden 
branching of the strand into its petiolar bundles just under 
the insertion of the leaf. This division occurs whilst the trace 
is still in the cortex, and the separating bundles diverge and 
pass sharply up into the petiole, where they are arranged 
round its periphery. A certain amount of anastomosis 
between the bundles in the petiole occurs, especially, as 
already stated, below the place where the leaf branches. 
Each bundle possesses phloem on its outer face, and 
parenchyma on the inner side of the xylem. This paren- 
chyma belongs to the bundle and may easily be mistaken 
for phloem, but a careful study has convinced us that these 
bundles are not concentric but truly collateral. The proto- 
xylem consists of a narrow band of elements on the inner 
side of the xylem, and they are often seen to border on a band 
of peculiar parenchyma similar to that which Russow 1 termed 
‘ Liicken-parenchymstreifen.’ 
The cells of this tissue are large and thin-walled. The 
transverse walls are clearly seen in longitudinal section, and 
the general impression which the observer acquires is that he 
is dealing with some kind of a gland. 
We endeavoured to ascertain whether there was any 
obvious difference between the proportion of phloem in the 
bundles distributed to the fertile and barren leaf-branches 
respectively ; but we are unable to detect any, although on 
a priori grounds it appeared not improbable that, having 
regard to the abundant sporangia, and consequent drain on 
plastic materials, such a difference might be found. 
As regards the venation of the blade of the leaf in 
Helminthostachys , it conforms in a general way with the type 
1 Russow, loc. cit., p. 104. 
G g 2 
