Table 1. Mean stomatal density, pore length, pore width, pore depth, maximum stomatal pore area, and theoretical maximum stomatal conductance (n = 4 ± sd) for the wild-type and Frizelliae forms of A. filix-femina.

Variety	Stomatal density	Pore length	Pore width	Pore depth	Maximum pore area	Maximum conductance
	mm2	μm	μm	μm	μm2	mol m−2 s−1
Wild type	33.7 ± 9.6	21.5 ± 2.6	3.5 ± 0.2	10.9 ± 1.5	58.8 ± 7.6	0.122 ± 0.03
Frizelliae	37.3 ± 5.0	14.9 ± 1.7	3.2 ± 0.5	10.8 ± 0.8	37.6 ± 10.1	0.096 ± 0.03