Quisling, Bharat, I don't like that clue very much - partly because it's inelegant (and long). I also wondered if 'great growth' is a good enough definition of 'araucaria'?
I tried anagram of US REPUBLICAN and T for tweeting as the 13th letter, could not get a satisfactory answer. PUBLIC NATURES?, not satisfied. Is T the 13 th letter or I ? Still screaming.