Sentence:  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 <WSD>persistent</WSD> lobes. 
Meaning of the word marked with <WSD> tags:  Lasting past maturity without falling off.