xylem have cell walls made of lignin
xylem has perforated cross walls
phloem has permeable cell walls
xylem tissue has companion cells
phloem cells contain cytoplasm
phloem occupy the center of the vascular bundle
substances in the xylem only move in one direction
both xylem and phloem have parenchyma
xylem and phloem contain tracheids
phloem cells develop a nucleus when they are mature
phloem tissue contains sclereids cells with extremely thick cell walls.
both xylem and phloem sieve tubes are made up of many cells joined end to end to form a long, hollow tube structure