Fig. 4.

Response of net CO₂ assimilation rate to intercellular CO₂ concentration in Homolepis aturensis, two C₂ species (Neurachne minor and Steinchisma hians), a C₄ species (Setaria viridis), a C₃ species (Dicanthelium oligosanthes), and a C₃ species with proto-Kranz anatomy (Steinchisma laxum). Measurement conditions were 31±1 °C and saturating light intensities (1200–1500 µmol m⁻² s⁻¹). The curves shown are representative of 2–3 individual A/C _i responses per species. The linear regression for points below 100 µmol mol⁻¹ is shown for H. aturensis (dashed line).