def trait_label(trait, sep=' '):
    """Generate a label for the trait."""
    label = [trait['part']]
    if 'subpart' in trait:
        label.append(trait['subpart'])
    label.append(trait['trait'])
    label = sep.join(label)
    label = label.replace('-', '')
    label = label.replace('indumentum' + sep + 'surface', 'indumentum')
    return label