Lilium regale seeds, with the internal embryos made visible using a strong background light. The embryos are the elongated structures running down the centre of the seeds. The rest of the seed consists of the casing and the food source (endosperm). Not all these seeds are fertile. Failure of seed development may be due to poor pollination of flowers or subsequent climatic conditions such as drought. L. regale is a species of lily native to China, used worldwide as a garden plant.