Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
inter-flŭo, fluxi, 3, v. n. and a. (in tmesi, Lucr. 4, 227), to flow between (rare but class.): quantum interfluit fretum, Liv. 41, 23, 16: angusto freto interfluente, Plin. 3, 5, 11, § 76.
With acc.: fretum, quod Naupactum et Ratras interfluit, Liv. 27, 29; cf.: flumen Visurgis Romanos interfluebat, Tac. A. 2, 9.
With dat.: interfluens urbi Tiberinus, Flor. 1, 4, 2; Sen. Ben. 6, 7, 3; Liv. 28, 23, 4.
Pass.: insulae interfluuntur (supply mari), App. de Mundo, p. 69 (but interfuissent is the true reading, Cic. de Sen. 6, 16).