THE ROOT BARK OF BIRCH (BETULA-PENDULA ROTH) - ANATOMY, DEVELOPMENT, IDENTIFICATION

The development of root bark structure of birch (Betula pendula ROTH) was analysed. With increasing distance from the stem less sclereids ar e formed, i.e, the formation of sclereids increases with root bark age . In root bark with less sclereids the dilatation of phloem rays is mo re distinct. With increasing distance from the stem the structural gro wth rhythm of the bark diminishes because of a delay in sieve tube col lapse and similar dimensions of early and late phloem elements. The cr ystal quantity decreases with increasing distance from the stem. In ro ots the specific phellem growth rhythm of birch bark is maintained. In young root bark, cells are present which differ from bark fibres as w ell as from typical sclereids. These cells are restricted to the outer area of young root bark. Their presence has to be considered during r oot bark identifications, because they are absent in stem bark which i s often used as reference material. However, the root bark structure o f birch exhibits sufficient qualitative characteristics to serve as a useful tool for root identifications.