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1. Dead cells .They are nonliving
at maturity.
2. Tubular cell.
3. Both are more or less
elongated cells that have
lignified secondary walls.
4. Form long columns, place
one above the other .
Similarity
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Difference
Tracheid
– Long, tubular cells with
tapering ends.
– Tracheids are
imperforate cells
having only pit-pairs
on their common
walls.
– Water flowing from
tracheids to tracheid
must pass through the
pit membranes of pit-
pair in their
overlapping wall
Vessel elements
• Cells are shorter . Cells
aren’t as tapering as
tracheids.
• Vessel elements are
perforated at their end.
• Perforations are areas
lacking both primary and
secondary walls through
which the vessel elements
are interconnected.
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Perforations plate
1. A single perforation (simple perforation
plate).
2. Several perforations (multiple
perforation plate)
• Scalariform perforation plate.
• Reticulate perforation plate.
• Foraminate perforation plate.
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Pits
• Simple and bordered pits are found in
the secondary walls of tracheid and
vessel elements of the latest formed
primary xylem and of the secondary
xylem
