Table 3. Phylogenetic signals (K-statistics) for 14 leaf functional traits from 30 fern species.

Trait	K-statistic	p
Leaf mass per unit area	0.396	0.009
Leaf density	0.289	0.045
Leaf water content	0.292	0.065
Cuticle thickness	0.329	0.422
Upper epidermal thickness	0.425	0.008
Lower epidermal thickness	0.282	0.134
Leaf thickness	0.382	0.016
Mesophyll thickness	0.363	0.019
Stomatal density	0.454	0.004
Stomatal length	1.322	0.001
Area-based maximum photosynthetic rate	0.360	0.012
Stomatal conductance	0.660	0.010
Transpiration rate	0.296	0.032
Vein density	0.632	0.005

K value <1 indicates that relatives resemble each other less than expected under Brownian motion evolution along the phylogenetic tree; K value >1 shows that close relatives are more similar than expected.