Wood anatomical report of Siberian species of Betula (Betulaceae

Abstract

The wood anatomy of six species of Betula from Siberia was described. These six species share typical wood anatomical characters of Betula in general. Two small shrubs, B. fruticosa subsp. montana and B. nana subsp. rotundifolia, are distinguished from the others in having smaller and shorter vessel elements, shorter fiber tracheids, shorter axial parenchyma strands, more numerous marginal cells of multiseriate rays. These two species consistently have shorter vessel elements, from near the pith throughout the secondary xylem to the outermost part, than a tree species, B. microphylla. It is discussed whether this feature is characteristic of the small shrubs of Betula.