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Betula humilis S
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Shrub Birch
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Betulaceae
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Transversal section |
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Diffuse-porous. Growth ring boundaries rather distinct, marked by 2 to 4 rows of radially flattened cells. According to some growth conditions these boundaries can be rather indistinct. Pores rather sparsely scattered, solitary, in radial multiples of 2 to 4 pores and in clusters. Pore size varies highly from one growing site to the other. Diffuse, sparse apotracheal parenchyma. Aggregate rays present, sometimes rare. |
      
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Radial section |
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Scalariform perforation plates with 10 to 15 (sometimes up to 25) bars. Homogeneous rays, occasionally square marginal cells. Ray-vessel pits numerous and extremely small. Libriform fibres present, fibre-tracheids absent. |
   
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Tangential section |
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Rays 2- to 4-seriate, also often uniseriate, in aggregate rays irregular cells. Average ray height: 10 to 25 cells. |
   
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Key characters |
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Diffuse-porous. Pores sparsely dispersed. Rays 2- to 4-seriate. Aggregate rays. Scalariform perforation plates. Ray-vessel pits numerous and extremely small. |
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Remarks |
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The wood of Betula humilis and Betula nana cannot always be differentiated on the basis of wood anatomy. |
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