Ancestral plants
were composed of units called Telomes
& Mesomes.
Telomes were Terminal segments.
Rhizome & Stem Apices would be Telomes.
Mesomes connected the Telomes.
(Meso = Middle like Mesophyll).
The Aerial Telomes could be
"Fertile" & bear terminal Sporangia.
Those that lacked Sporangia (vegetative)
were called Phylloides (Phyll = Leaf)
All of the above had an interconnected
Vascular System (Protostele)