C. L. Schwartz and H. J. Arnott. Lotus flowers are large, about 20cm in diameter when fully opened, and extend above water level on a long, thin petiole. The flowers do not have sepals, but have 10-20 petals that are arranged around a large, central receptacle. Lotus flowers contain up to 200 stamens surrounding the receptacle as well. The conical receptacle or carpophore contains up to 20 carpels.
Large airspaces give the receptacle a spongy texture.
Calcium oxalate crystals are found lining these airspaces. The petals of lotus also have papillose epidermal cells. However, the crystals are not found on multicellular trichomes, but in single-celled idioblasts. Calcium oxalate crystal druses line the airspaces found at the base of the petals. The stamens of lotus have a short filament with the anther about twice as long as the filament.