(botany) In liverworts with bilobed leaves, the smaller of the two lobes, sometimes modified to form a sac.
Schuster Hepaticae V|4The 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.
