A luminous, willowy blonde, Laura Dern is a rare hybrid of character actress and movie star. With role models like father Bruce Dern, mother Diane Ladd and godmother Shelly Winters, it's little wonder that she grew up unafraid to tackle unglamorous roles, acquiring a reputation as a risk-taker who lives and dies by the "authenticity" of her work. Conceived during the filming of Roger Corman's "The Wild Angels" (1966, in which both parents acted), she remembers seeing at an early age her father's severed head bounce down the stairs when "Hush ... Hush, Sweet Charlotte" (1965) played on TV. Dern