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 are formed, i.e, the formation of sclereids increases with root bark age. In root bark with less sclereids the dilatation of phloem rays is more distinct. With increasing distance from the stem the structural growth rhythm of the bark diminishes because of a delay in sieve tube collapse and similar dimensions of early and late phloem elements. The crystal quantity decreases with increasing distance from the stem. In roots the specific phellem growth rhythm of birch bark is maintained. In young root bark, cells are present which differ from bark fibres as well as from typical sclereids. These cells are restricted to the outer area of young root bark. Their presence has to be considered during root bark identifications, because they are absent in stem bark which is often used as reference material. However, the root bark structure of birch exhibits sufficient qualitative characteristics to serve as a useful tool for root identifications.