EDIT

modules/cdm_dataportal/classes/footnote.php -text

modules/cdm_dataportal/classes/footnotemanager.php -text

modules/cdm_dataportal/js/footnotes.js -text

.footnote{

	font-size: 90%;

}

.footnote-key{

  vertical-align: super;

  font-size: 80%;

  font-style: italic;

}

require_once('classes/footnotemanager.php');

require_once('classes/footnote.php');

function _add_js_footnotes(){

  drupal_add_js(drupal_get_path('module', 'cdm_dataportal').'/js/footnotes.js');

}

				$block->content = theme('cdm_descriptionElements', $node->descriptionElements, $node->feature->uuid);

/**

 * Theme a list of description elements, usually of a specific feature type

 * @param $descriptionElements

 * @return unknown_type

 */

function theme_cdm_descriptionElements($descriptionElements, $featureUuid){

	$distributionElements = array();

				$distributionElements[]= $descriptionElement;

				$repr = theme ('cdm_descriptionElementTextData', $descriptionElement, $asListElement);

	$outArray[] = theme('cdm_descriptionElementDistribution', $distributionElements);

	$out = theme('cdm_descriptionElementArray', $outArray, $feature, $glue, $sortOutArray, $enclosingHtml);

	$out .= '<div class="footnote_list">'. FootnoteManager::renderFootnoteList($featureUuid) . '</div>';

	return $out;

	$out = '';

	$separator = ', ';

	foreach($descriptionElements as $descriptionElement){

		//$footnoteKey = FootnoteManager::addNewFootnote($descriptionElement->feature->uuid, $descriptionElement->area->representation_L10n);

	  $footnoteKeyList = '';

		foreach($descriptionElement->sources as $source){

  		$footnoteKey = FootnoteManager::addNewFootnote($descriptionElement->feature->uuid, $source, 'cdm_DescriptionElementSource');

  		$footnoteKeyList .= theme('cdm_footnode_key', $footnoteKey) . ' ';

		}

    $out .= $descriptionElement->area->representation_L10n . $footnoteKeyList . $separator;

	$out = substr($out, 0, strlen($out)-strlen($separator) );

//  $referenceCitation = l('<span class="reference">('.$reference->title.')</span>', path_to_reference($reference->uuid), array("class"=>"reference"), NULL, NULL, FALSE ,TRUE);

//	if($descriptions && strlen($descriptions) > 0 ){

//		$sourceRefs .= ' '.$referenceCitation;

//	}

	return $out;

}

function theme_cdm_DescriptionElementSource($descriptionElementSource, $doLink = TRUE){

    //ev. delegate to theme_cdm_ReferencedEntityBase

    $out = '';

    if($descriptionElementSource->citation){

      $datePublished = $descriptionElementSource->citation->datePublished;

      if (strlen($datePublished->start) >0){

        $year=substr($datePublished->start,0,strpos($datePublished->start,'-'));

      }

      $author_team_titlecache = $descriptionElementSource->citation->authorTeam->titleCache;

      if (strlen($year)>0){

        $reference = $author_team_titlecache.' '. $year;

      }else {

        $reference = $author_team_titlecache ;

      }

      if($doLink){

        $out = l('<span class="reference">'.$reference.'</span>'

          , path_to_reference($descriptionElementSource->citation->uuid)

          , array("class"=>"reference")

          , NULL, NULL, FALSE ,TRUE);

      } else {

       $out = $reference;

      }

      if($descriptionElementSource->citationMicroReference){

        $out .= ': '. $descriptionElementSource->citationMicroReference;

      }

    }

    return $out;

    $referenceCitation = theme('cdm_DescriptionElementSource', $source);

    if($description && strlen($description) > 0 && $referenceCitation ){

        $sourceRefs .= ' ('.$referenceCitation.')' ;

  return $res_text;

function theme_cdm_footnode_key($footnoteKey){

  $out = '<a href="#footnote-'.$footnoteKey.'" class="footnote-key">'.$footnoteKey.'</a>';

  return $out;

}

function theme_cdm_footnode($footnoteKey, $footnodeText){

  _add_js_footnotes();

  $out = '<span class="footnote footnote-'.$footnoteKey.'"><a name="footnote-'.$footnoteKey.'"></a><span class="footnote-anchor">'.$footnoteKey.'.</span>&nbsp;'.$footnodeText.'</span>';

  return $out;

}

<?php

class Footnote

{

    public $key, $object, $theme, $themeArguments;

    // private constructor

    public function __construct($footnoteKey, $object, $theme = null, array $themeArguments = array()) {

        $this->key = $footnoteKey;

        $this->object = $object;

        $this->theme = $theme;

        if(!is_array($themeArguments)){

          $themeArguments = array();

        }

        $this->themeArguments = $themeArguments;

    }

    public function doRender(){

      if($this->theme){

      $args = $this->themeArguments;

      array_unshift($this->object);

      array_unshift($this->theme);

        $out = call_user_func_array('theme', $args);

      } else {

        $out = $this->object;

      }

      return theme('cdm_footnode', $this->key, $out);

    }

}

<?php

class FootnoteManager

{

    private static $fnstore = array();

    private static $nextFootnoteKey = 1;

    // private constructor

    private function __construct() {

    }

    /**

     * @param $footnoteListKey a string as key to the list of footnotes

     * @return an array of footnotes objects

     *  

     */

    public static function getFootnoteList($footnoteListKey){

      return array_key_exists($footnoteListKey, self::$fnstore) ? self::$fnstore[$footnoteListKey] : NULL;

    }

    /**

     * 

     * @param $footnoteListKey

     * @param $separator

     * @return unknown_type

     */

    public static function renderFootnoteList($footnoteListKey, $separator = ', '){

      $out = '';

      if(array_key_exists($footnoteListKey, self::$fnstore)){

        foreach(self::$fnstore[$footnoteListKey] as $fn){

          $out .= $fn->doRender() . $separator;

        }

        $out = substr($out, 0, strlen($out)-strlen($separator));

      }

      return $out;

    }

    /**

     * 

     * @param $footnoteListKey

     * @param $object

     * @param $theme

     * @param $themeArguments

     * @return unknown_type

     */

    public static function addNewFootnote($footnoteListKey, $object, $theme = NULL, $themeArguments = array()){

      if(!array_key_exists($footnoteListKey, self::$fnstore)){

          self::$fnstore[$footnoteListKey] = array();

      }

      $fnKey = NULL;

      if( !($fnKey = self::footnoteExists($footnoteListKey, $object)) ){

        $fnKey = self::$nextFootnoteKey++;

        $fn = new Footnote($fnKey, $object, $theme, $themeArguments);

        self::$fnstore[$footnoteListKey][$fnKey] = $fn;

      }

      return $fnKey;

    }

    /**

     * 

     * @param $footnoteListKey

     * @param $object

     * @return unknown_type

     */

    private static function footnoteExists($footnoteListKey, $object){

      foreach(self::$fnstore[$footnoteListKey] as $key=>$fn){

        /**

         * When using the comparison operator (==), object variables are compared in a simple manner, namely: 

         * Two object instances are equal if they have the same attributes and values, and are instances of the same class. 

         */

        if($object == $fn->object){

          return $key;

        }

      }

      return FALSE;

    }

    // stop users from cloning

    public function __clone() {

        trigger_error('Cloning instances of the singleton class FootNoteManager is prohibited', E_USER_ERROR);

    }

}

if (Drupal.jsEnabled) {

  $(document).ready($(document).ready(function() {

	  function getFootnoteClassName(object){

		  return '.'+$(object).attr('href').substr(1);

	  }

	  $('a.footnote-key').mouseover(function(e){

		  var fnClassName = getFootnoteClassName(this);

		  $('.footnote').css('background-color', 'transparent').css('background-color', 'transparent').removeClass('active');

		  $(fnClassName).css('background-color', 'yellow');

	  	}

	  ).mouseout(function(e){

		  var fnClassName = getFootnoteClassName(this);

		  $(fnClassName).not('.active').css('background-color', 'transparent');

	  	}

	  ).click(function(e){

		  var fnClassName = getFootnoteClassName(this);

		  $('.footnote').css('background-color', 'transparent').removeClass('active');

		  $(fnClassName).css('background-color', 'yellow').addClass('active');

	  });

  }));

}

function palmweb_2_cdm_descriptionElementDistribution($descriptionElements) {

  $descriptions = '';

  $separator = ', ';

  foreach($descriptionElements as $descriptionElement){

    $descriptions .= $descriptionElement->area->representation_L10n . $separator;

  }

  $descriptions = substr($descriptions, 0, strlen($descriptions)-2);

  $taxonTrees =  cdm_ws_get(CDM_WS_TAXONOMY);

  foreach($taxonTrees as $taxonTree){

    if ($taxonTree -> uuid == variable_get('cdm_taxonomictree_uuid', FALSE)){

      $reference = $taxonTree-> reference;

      break;

    }

  }

  $out = substr($out, 0, strlen($out)-strlen($separator) );

  $referenceCitation = '('.l('<span class="reference">World Checklist of Monocotyledons</span>', path_to_reference($reference->uuid), array("class"=>"reference"), NULL, NULL, FALSE ,TRUE).')';

  if($descriptions && strlen($descriptions) > 0 ){

    $sourceRefs .= ' '.$referenceCitation;

  }

  if(strlen($sourceRefs) > 0){

    $sourceRefs = '<span class="sources">' . $sourceRefs . '</span>';

  }

  return $descriptions. $sourceRefs ;

}