It's Canna - or Canna lily, although it's not a true lily - a unique genus of nineteen species of flowering plants. In fact, Canna is the only genus in the family Cannaceae. The closest living relations to cannas are the other plant families of the order Zingiberales - gingers and bananas and bananas and such. So it's unique and gaudy and absurd - and in bloom all over Hollywood, of course, as Hollywood is equally unique and gaudy and absurd.