For his spring Brooks Brothers women’s collection, Zac Posen looked no further than the incubator of summery preppy-isms that is Palm Beach, Fla., for his references. Out came pink-and-black, florals, madras, seersucker and tropical prints, which Posen paired with fit-and-flare shirtdresses, twinsets, tunics, palazzo pants and updates on the tidy Sixties suit. There were many easy, wearable — if a bit kitschy — classics that would do well blended with a modern casual sportswear, but Posen should be careful not to dive so deep into Brooks Brothers traditional side that things turn dowdy.