The Jubulaceae have a leaf whose lobule, usually transformed into a water-sac, is normally very narrowly attached to the stem and to the dorsal lobe; indeed some Frullania taxa reproduce vegetatively by dropping the dorsal lobes, but not the lobules, and Neohattoria has caducous lobules but persistent lobes.
1992, Rudolf M[athias] Schuster, The Hepaticae and Anthocerotae of North America: East of the Hundredth Meridian, volume V, New York, N.Y.: Columbia University Press, page 4