a welcome , if downbeat , missive 
(ROOT (NP (DT a) (ADJP (JJ welcome)) (, ,) (SBAR (IN if) (FRAG (ADJP (JJ downbeat)))) (, ,) (NN missive)))
(ROOT (NP (DT ) (ADJP (JJ )) (, ) (SBAR (IN ) (FRAG (ADJP (JJ )))) (, ) (NN )))