Table 1.

Symbols for Fig. 2

Quantity	Symbol	Units
Conductance	g	mol m−2 s−1
CO2 mol fraction	c	mol mol−1
H2O mol fraction	e	mol mol−1
CO2 flux	A	mol m−2 s−1
H2O flux	E	mol m−2 s−1
Sub-stomatal cavity (SSC) radius	b	m
Stomatal pore radius	a	m
Stomatal pore depth	L	m
Subscripts		Symbol
Interior to stomata (in sub-stomatal cavity)		i
Ambient		a
Stomatal		s
With respect to CO2		c
With respect to H2O		w
Intercellular airspace		ias
Mesophyll		m
Boundary layer		bl
Isotopic notation		Symbol
δ18O of CO2 within the chloroplasts		δ c
δ18O of CO2 interior to the stomata		δ i
δ18O of CO2 in equilibrium with evaporation sites		δ c,e
δ18O of H2O at the evaporation sites		δ e