This micrograph shows part of the stele in
detail. Note the thin bands of phloem, in which a one-cell wide strand of
sieve cells, (SS, with clear lumina) surrounded by darkly-stained
parenchyma and albuminous cells is present between the xylem
strands. The central row of sieve cells, which are surrounded by darkly-staining
The xylem is composed of tracheids (T) of variable width - between 2 to about 8 µm in diameter.