In this cross section,
one can clearly see that this stem has a well-developed
periderm (Per) beneath which is a broad band of
sclerenchymatous phloem fibres (Sc). At
least three bands of phloem are evident in this section
each of which is associated with darkly-staining
tanniniferous and or mucilaginous cells.
Beneath the secondary phloem (2P), is a narrow cambial zone (CZ)
separates the cambium from the secondary xylem (2X).
The large xylem vessels within the secondary are
solitary, occurring in files, and
surrounded by bands of lignified fibres as well as
lignified parenchymatic elements. The parenchyma within
the secondary xylem occurs in narrow concentric zones or
bands, varying from narrow strands, to completely
encircling the solitary large-diameter secondary xylem
vessels. This is described as aliform-confluent
Apotracheal means parenchyma bands
that are mainly independent of the vessels;
Paratracheal means parenchyma
associated with vessels.
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