betula alba

Betulin \Bet"u*lin\, n. [L. betula birch tree.] (Chem.)
   a term originally applied to a substance obtained as a resin
   or tar by extraction from the outer bark of the common
   European white birch ({Betula alba}); now referring to the
   chemical compound ({C30H50O2}) having a
   cyclopentanophenanthrene ring system, which is the main
   constituent of that extract, and which may be obtained
   crystalline; -- called also {birch camphor}. --Watts.
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Birch \Birch\ (b[~e]rch), n.; pl. {Birches} (-[e^]z). [OE.
   birche, birk, AS. birce, beorc; akin to Icel. bj["o]rk, Sw.
   bj["o]rk, Dan. birk, D. berk, OHG. piricha, MHG. birche,
   birke, G. birke, Russ. bereza, Pol. brzoza, Serv. breza, Skr.
   bh[=u]rja. [root]254. Cf. 1st {Birk}.]
   1. A tree of several species, constituting the genus
      {Betula}; as, the white or common birch ({Betula alba})
      (also called silver birch and lady birch); the dwarf birch
      ({Betula glandulosa}); the paper or canoe birch ({Betula
      papyracea}); the yellow birch ({Betula lutea}); the black
      or cherry birch ({Betula lenta}).
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   2. The wood or timber of the birch.
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   3. A birch twig or birch twigs, used for flogging.
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   Note: The twigs of the common European birch (B. alba), being
         tough and slender, were formerly much used for rods in
         schools. They were also made into brooms.
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               The threatening twigs of birch.    --Shak.
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   4. A birch-bark canoe.
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   {Birch of Jamaica}, a species ({Bursera gummifera}) of
      turpentine tree.

   {Birch partridge}. (Zool.) See {Ruffed grouse}.

   {Birch wine}, wine made of the spring sap of the birch.

   {Oil of birch}.
      (a) An oil obtained from the bark of the common European
          birch ({Betula alba}), and used in the preparation of
          genuine (and sometimes of the imitation) Russia
          leather, to which it gives its peculiar odor.
      (b) An oil prepared from the black birch ({Betula lenta}),
          said to be identical with the oil of wintergreen, for
          which it is largely sold.
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