Persian silk tree: Albizia's flowers look like thousands of strands of silk threads growing from the calyx. Since the specific epithet, julibrissin means silk flower in Persian, this genus is called a silk tree. As this plant is originated from Persia, it is called the Persian silk tree.
Mimosa tree: The leaves look similar to mimosa but it does not close up like mimosa when touched. Its leaves only close slowly at night and bow downward which looks similar to the closed-up mimosa. Hence, it is called the mimosa tree.