Liber /(lī"bẽr)/

Li·ber

Liber

n.
  1. The inner bark of plants, lying next to the wood. It usually contains a large proportion of woody, fibrous cells, and is, therefore, the part from which the fiber of the plant is obtained, as that of hemp, etc. (Bot.)

Phrases & Compounds
Liber cells
elongated woody cells found in the liber.