“…Stomatal conductance is determined by anatomical characteristics, including stomatal density (SD), size (guard cell length; GCL) and patterning, as well as by functional responses that alter pore aperture (Willmer & Fricker, 1996; Weyers & Lawson, 1997; Hetherington & Woodward, 2003; Casson & Hetherington, 2010; Lawson & Blatt, 2014; Matthews et al ., 2018; Faralli et al ., 2020). Stomatal density is known to vary within (Weyers & Lawson, 1997; Weyers et al ., 1997) and between species (Ticha, 1982) and is also dependent on growth conditions (Woodward, 1987; Morison & Lawson, 2007; Stevens et al ., 2021). The distribution of stomata can either be confined to one leaf surface – the abaxial surface (hypostomatous), or much less commonly, the adaxial surface (hyperstomatous) – or they can be present on both (amphistomatous; Parkhurst, 1978), which is the most conventional arrangement.…”