Sentence:  The Jubulaceae have a leaf whose <WSD>lobule</WSD>, 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 <WSD>lobules</WSD>, and "Neohattoria" has caducous <WSD>lobules</WSD> but persistent lobes. 
Meaning of the word marked with <WSD> tags:  In liverworts with bilobed leaves, the smaller of the two lobes, sometimes modified to form a sac.