[医] 韧皮的, 自由的, 游离的

Liber \Li"ber\ (l[imac]"b[~e]r), n. [L. See {Libel}.] (Bot.)
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.

{Liber cells}, elongated woody cells found in the liber.