Fig. 6.

The relative differences in N percentage between lamina without mid-rib and lamina with mid-rib in relation to whole-lamina (lamina and mid-rib) fresh mass (A), and the corresponding differences in N percentage between lamina without mid-rib and whole-leaf (B) in relation to whole-leaf fresh mass. Data presentation and fitting for 122 species as in Fig. 3. Relative differences are defined in Fig. 4. All regressions are significant at P < 0·001. The arrows denote outlying observations for Leontodon taraxacoides (Fig. 3). The explained variances without this outlying observation were r² = 0·37 for A and r² = 0·52 for B.