In some mycelium, hypha when formed is compartmentally divided into small partitions or cross walls called as septa (single compartment called as septum).This septum has the ability to cut off a segment completely or incompletely. When the septum is cut incompletely, a gap is formed called as central pore in the middle and when it is formed in a particular septum it is called simple central pore.The pore helps in the easy passage of nuclei and other cytoplasmic inclusions between different cells of hyphae.
Septum with complex pore is called dolipore. They are dividing walls between the septa which have a barrel shaped swelling aroiund the simple central pore. Dolipore septum when formed has the ability pass through complete cell organelles because it is very wide.