Thanks for all your responses. Yes, I have been peering down some
microscopes at Buxus specimens. What I am particularly interested in
is what I can only describe as a "rim" on the edge of the leaf. Inside
the rim there appear to be bundles of fibres, which seem to be
possibly silicified (very resistant to ashing and pinkish in colour in
Canada balsam). I have checked various anatomy books and this kind of
structure does occur in other dicot leaves, but what I am after is
confirmation that my interpretation of this case is correct.
Best Wishes,
Martin