Bermadinger-Stabentheiner E & Stabentheiner A 1995. Dynamics of thermogenesis and structure of epidermal tissues in inflorescences of Arum maculatum L. New Phytologist 131: 41-50.
The Arum lily (Arum maculatum) is a typical gliding trap inflorescence ("Gleitfallenblume"). The spadix of the inflorescence consists of separate male and female flowers at the base and a sterile club at the tip - the appendix. During flowering the spathe unfolds in its upper part and exposes the appendix whereas the lower part, forming the floral chamber (basal bulb) with the male and female flower parts, remains closed to trap small insects. The appendix and parts of the sexual organs heat up via combustion of starch, to improve vaporisation of in part bad smelling 'odour', which attracts the insects. We (Edith and Anton Stabentheiner) compare the (thermal) characteristics and temporall patterns of flowering phases of different Aroid plants.
Infrared thermogram of a flowering Arum lily inflorescence (Arum maculatum) - the male flowers in the floral chamber (bottom, light blue) and the sterile appendix (top, yellow) are heated up to 15°C above ambient temperature to release odours that attract small flies (Psychoda sp.) which pollinate the flowers (real duration: ca. 24 h)