Based on field observations and some discussions with U.S.
( Based ( on ( ( ( field observations ) and ) ( ( some discussions ) ( with U.S. ) ) ) ) )
(ROOT (PP (VBN Based) (PP (IN on) (NP (NP (NN field) (NNS observations)) (CC and) (NP (NP (DT some) (NNS discussions)) (PP (IN with) (NP (NNP U.S.))))))))
It had no basis, just pure speculation. 
( It ( ( had ( ( ( ( no basis ) , ) just ) ( pure speculation ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBD had) (NP (NP (DT no) (NN basis)) (, ,) (RB just) (NP (JJ pure) (NN speculation)))) (. .)))