On her third album, London-based musician Billie Marten takes her minimalist acoustic foundation and grows a verdant, beautiful landscape all over it. Like the single, “Garden of Eden,” Flora Fauna is an exemplar of growth: Marten’s signature breathy, tender vocals swim amidst rich, abounding instrumentation including horns, strings, toe-tapping beats, and drums and bass which enliven these pop songs. She strikes a cunning balance of play and contemplation, joy and longing. And her lyrics, which always express quiet truths about her inner experience, now sparkle with optimism....