herbarium/templates/species/_delete_form.html.twig

<form method="post" action="{{ path('app_species_delete', {'id': species.id}) }}" onsubmit="return confirm('{{ 'delete_item_confirmation'|trans }}');">
    <input type="hidden" name="_token" value="{{ csrf_token('delete' ~ species.id) }}">
    <button class="btn btn-danger">{{ 'delete'|trans }}</button>
</form>