Figure 4.

Morphospace (d : δ) of vein placement in leaves of ferns, gymnosperms and angiosperms. Flowering plants are subdivided into derived angiosperms (Laurales, core eudicots, monocots except Acorales and Alismatales) and basal angiosperms (ANITA-grade taxa, all magnoliids except Laurales, the basal eudicot Ranunculales and Proteales, and the basal monocot Acorales and Alismatales). Values of d and δ are species averages (see the electronic supplementary material, table S1), not individual measurements. Standard deviations reported reflect variation of d and δ between leaves within each species, not between individual measurements within each leaf. Dashed line represents the optimal d/δ ratio of 1 : 1. Dashed double-dotted line is a linear fit of derived angiosperm plants only with dotted line representing 95% CI. Main graph axes are limited to 1.5 mm distances. Inset graph includes all sampled plants. (Online version in colour.)