EDIT

  // 1. scan this level

  foreach ($feature_tree_nodes as $node){

      return $node;

    }

  }

    // Append corresponding elements to an additional node field:

    // $node->descriptionElements.

    foreach ($descriptionElements as $element) {

        if (!isset($node->descriptionElements)) {

          $node->descriptionElements = array();

        }

  foreach ($root_node->childNodes as $feature_node) {

    $out .= ($out ? $separator : '');

      if (is_array($feature_node->childNodes) && count($feature_node->childNodes) > 0) {

        $childlabels = cdm_featureTree_elements_toString($feature_node, $separator, $field_name);

        if (strlen($childlabels)) {

    if ($childIndent) {

      $indent_prefix = $childIndent . $node_char . " ";

    }

    if (isset($featureNode->childNodes) && is_array($featureNode->childNodes)) {

      // Foreach ($featureNode->childNodes as $childNode){

      $childList = _featureTree_nodes_as_feature_options($featureNode, $node_char, $childIndentStr, $childIndent . $childIndentStr);

    $feature_tree = get_csv_featureTree();

    if (isset($feature_tree->root->childNodes)) {

        foreach ($feature_tree->root->childNodes as $featureNode) {

                // Must not exceed 45 characters !!!

                //        $settings = mixed_variable_get($subform_id, FEATURE_TREE_LAYOUT_DEFAULTS);

                //        $systemDefaults = unserialize(FEATURE_TREE_LAYOUT_DEFAULTS);

                $form['redListField']['csvExportOptions'][$subform_id] = array(

                    '#type' => 'checkbox',

                        'name' => 'features'

                    ),

                );

    RenderHints::pushToRenderStack('feature_block');

    // Create a drupal block for each feature

        $block->content = array();

        $block_content_is_empty = TRUE;

          // do not show features which belong to the UseDescriptions, these are

          // handled by compose_feature_block_items_use_records() where the according descriptions are

          // fetched again separately.

        /*

         * Content/DISTRIBUTION.

         */

          $block_content_is_empty = FALSE;

        }

        /*

         * Content/COMMON_NAME.

         */

          $block->content[] = $common_names_render_array;

          $block_content_is_empty = FALSE;

        }

        /*

         * Content/Use Description (Use + UseRecord)

         */

          $block_content_is_empty = FALSE;

        }

          $elements_render_array = array();

          $child_elements_render_array = null;

          }

          // Content/ALL OTHER FEATURES/Subordinate Features

          // subordinate features are printed inline in one floating text,

          // it is expected hat subordinate features can "contain" TextData,

          // Qualitative- and Qualitative- DescriptionElements

            $elements_render_array = array_merge($elements_render_array, $child_elements_render_array);

          }

          $block_content_is_empty = $block_content_is_empty && empty($media_list) && empty($elements_render_array);

          if(!$block_content_is_empty){

            /*

             * Footnotes for the feature block

             */

          }

        } // END all other features

        // allows modifying the block contents via a the hook_cdm_feature_node_block_content_alter

        if(!$block_content_is_empty){ // skip empty block content

          $block_list[] = $block;

        } // END: skip empty block content

      } // END: skip empty or suppressed features

      RenderHints::popFromRenderStack();

 *

 * This function is called recursively!

 *

 *   The feature node.

 * @param array $media_list

 *   List of CDM Media entities. All media of subordinate elements should be passed to the main feature.ä

 *

 * @ingroup compose

 */

{

  if(!$main_feature){

  }

  /*

   * TODO should be configurable, options; YES, NO, AUTOMATIC

  $prepend_feature_label = false;

  $render_arrays = array();

    if (isset($child_node->descriptionElements[0])) {

      foreach ($child_node->descriptionElements as $element) {

  /**

   *

   *  The merged feature three node which potentially contains media in its description elements.

   * @param $media_list

   *    Additional media to be merged witht the media contained in the nodes description elements

   *

   * @ingroup compose

   */

    }

    $captionElements = array('title', 'rights');

    if (isset($media_list[0]) && isset($gallery_settings['cdm_dataportal_media_maxextend']) && isset($gallery_settings['cdm_dataportal_media_cols'])) {

      $gallery = compose_cdm_media_gallerie(array(

        'mediaList' => $media_list,

        'maxExtend' => $gallery_settings['cdm_dataportal_media_maxextend'],

        'cols' => $gallery_settings['cdm_dataportal_media_cols'],

        'captionElements' => $captionElements,

    // creating helper object to retrieve the default settings

    $featureNode = new stdClass();

    array_unshift($profile_feature_tree->root->childNodes, $featureNode);

    foreach ($profile_feature_tree->root->childNodes as $featureNode) {

        // $subform_id must not exceed 45 characters, a uuid has 36 characters

//        $settings = mixed_variable_get($subform_id, FEATURE_TREE_LAYOUT_DEFAULTS);

        $form_feature_block_layout[$subform_id] = array(

          '#type' => 'fieldset',

          '#tree' => TRUE,

          '#collapsible' => FALSE,

          '#collapsed' => FALSE,

        );

          $form_feature_block_layout[$subform_id]['#description']='These are the defaults which apply to

          all feature blocks for which no specific settings have been defined. for consistency enabling links for <em>source

          references</em> and <em>names in source</em> is only possible in the defaults';

          ),

        );

          $form_feature_block_layout[$subform_id]['link_to_reference'] = array(

            '#type' => 'checkbox',

            '#title' => t('Link to reference'),

 */

function theme_FeatureTree_hierarchy_children($variables) {

  $out = '';

      }

      $out .= '</li>';

    }