2.2 Plant material
Plants were obtained from specialist nurseries and from the living collections of the Royal Botanic Gardens, Kew (UK) (Table 1 ). All species were potted in a mix of 1:1 pumice:sand, except C. multicava , C. ovata , C. perforata which were potted in a mix of 1:3:3 potting mix:pumice:sand. All plants were grown in a greenhouse with 12-hour days and 20/17°C day/night temperatures. The methods described below were applied, for each species, to the part of the leaf where water uptake was more likely, due to the presence and/or higher abundance of hydathodes (see Table 2 ).