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    ACKNOWLEDGEMENTS 
       I thank the Directors of the following herbaria for loans of material
      and asistance during visits: BK, BKF, BM, C, CMU, E, KUN, L, P,
      SGN, YUNU. Thanks also to Dr A. Hay and Dr David A. Simpson for
      helpful comments and suggestions, Mr Alan R. Radcliffe-Smith for
      translating the diagnosis into Latin and Emmanuel Papadopoulos for
      the illustrations.  
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