Heat induced injuries in leaves of three alpine dwarf shrubs. A. R. ferrugineum, B. V. gaultherioides and C. L. procumbens. Heat treatment was performed in situ with the Heat Tolerance Testing System under full natural solar irradiation during summer 2012 on Mt. Patscherkofel (1960 m a.s.l.). As in these species damaged leaf areas show typical, sharped - edged discolorations (arrows) the proportion of damaged to intact leaf area per leaf can easily be determined. Black line: 1 cm.