Angiosperms stand out due to their high variability in the construction of the vascular cylinder, although the basic patterns are mostly identical. Nevertheless does a serious difference between mono- and dicots exist. The situation in dicots is closer to the basic pattern and is therefore discussed first. Variations of the vascular cylinder are based upon direction and height of the helix, upon the number of traces per leaf and the nature of leaf insertion. The term leaf gap that has to be mentioned in this context denotes a gap in the vascular cylinder above the leaf insertion.
Angiosperms do as a rule contain five strands of vascular bundles.
This number is regarded as a basic unity, of which variations with more or less chords are derived. Here, the basic pattern shows four vascular bundles per vascular chord. Their vascular cylinder looks net-like . Exceptions, transitions and degenerations can be found in many dicots. Often can two or more types be found within one plant.