bark(redirected from white willow bark)
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1. The envelope or covering of the roots, trunk, and branches of plants. Barks of pharmacologic significance not listed below are alphabetized under specific names.
2. Synonym(s): cinchona
Farlex Partner Medical Dictionary © Farlex 2012
The outer covering of trees and some plants, which consists of a cuticle (epidermis), outer bark (cortex) and inner bark (fibre).
(1) China, see there.
(2) Cinchona, see there; Cinchona species.
The harsh sound uttered by a dog.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
barkthe outer, living part of a woody stem, consisting of three layers:
- an inner layer called secondary PHLOEM, containing the elements of primary phloem plus horizontal ray cells which function in transporting materials across the stem.
- a middle layer of cork CAMBIUM, a group of meristematic (dividing) cells originating in the PARENCHYMA cells of the outer stem cortex. As the cells divide, the outer ones develop into cork cells and the inner ones give rise to parenchyma-like tissue.
- CORK, an outer region of cells forming a waterproof and protective layer broken only by LENTICELS.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005