A nuclear membrane, also known as the nuclear envelope, nucleolemma or karyotheca, is the double lipid bilayer membrane which surrounds the genetic material and nucleolus in eukaryotic cells.
The nuclear membrane consists of two lipid bilayers - the inner nuclear membrane, and the outer nuclear membrane. The space between the membranes is called the perinuclear space, a region contiguous with the lumen (inside) of the endoplasmic reticulum.
The nuclear membrane has many small holes called nuclear pores that allow material to move in and out of the nucleus.
Rough endoplasmic reticulum produces nuclear envelope in telophase.