The paper presents data on the thermogenic blossom of the giant tropical water lily Victoria cruziana investigated in a greenhouse of the Berlin Botanical Gardens. Usual mercury and handhold non-contact infrared (IR) thermometers rendered temperature increases of up to 9 K compared with the ambient air. Continuously registering data loggers evaluated the temporal thermal structure of the flower during blooming. Temperature distributions in the blossom and on the floating green leaves were determined by means of a transportable IR thermographic camera. Moreover, it showed the puzzling phenomenon of thermal reflection of flowers and leaves which is discussed in some details.