drush error about taxonomy_xml_lookup_services()

Attempting to list features with drush fe after taxonomy_xml installation results in:

PHP Fatal error:  Call to undefined function taxonomy_xml_lookup_services() in /drupal/sites/all/modules/taxonomy_xml/taxonomy_xml.features.inc on line 27
PHP Stack trace:
PHP   1. {main}() /drush/drush.php:0
PHP   2. drush_main() /drush/drush.php:14
PHP   3. _drush_bootstrap_and_dispatch() /drush/drush.php:57
PHP   4. drush_dispatch() /drush/drush.php:88
PHP   5. call_user_func_array() /drush/includes/command.inc:225
PHP   6. drush_command() /drush/includes/command.inc:225
PHP   7. _drush_invoke() /drush/includes/command.inc:946
PHP   8. call_user_func_array() /drush/includes/command.inc:125
PHP   9. drush_features_export() /drush/includes/command.inc:125
PHP  10. features_invoke() /drupal/sites/all/modules/features/features.drush.inc:184
PHP  11. call_user_func_array() /drupal/sites/all/modules/features/features.module:435
PHP  12. taxonomy_xml_source_features_export_options() /drupal/sites/all/modules/features/features.module:435