I see what you mean, but they are definitely not Lilium seed. They look like Alyssoides seed. A. utriculata is a commmon imposter of Erysimum capitatum in seed exes. Nevertheless, still a plant worth growing. Dark yellow flowers over brown (sometimes almost black) sepals can be striking. Makes nice seed pods for dried bouquets. You can use the raceme of egg shaped light brown pods, or wait until they dehisce like L.unaria or Fibigia, producing little oval translucent windows:
Fibigia clypeata
