is , by itself , deserving of discussion 
(ROOT (VP (VBZ is) (, ,) (PP (IN by) (NP (PRP itself))) (, ,) (ADJP (JJ deserving) (PP (IN of) (NP (NN discussion))))))
(ROOT (VP (VBZ ) (, ) (PP (IN ) (NP (PRP ))) (, ) (ADJP (JJ ) (PP (IN ) (NP (NN ))))))