Fig. 3.

Light-response curves for photosynthetic CO₂ assimilation, measured by infra-red gas analysis. All are from the same localities as in Tables 1 and 2, but except for (C) on different sampling occasions. In general, ‘photosynthesis’ (plotted as a fraction of the asymptote of the fitted curve) has been taken as the sum of net CO₂ uptake and dark respiration, adjusted in (C) where the form of the curve indicated that dark respiration was over-estimated. (A) Andreaea rothii, PPFD_95% 551 µmol m⁻² s⁻¹; (B) Racomitrium aquaticum, PPFD_95% 583 µmol m⁻² s⁻¹; (C) Tortula (Syntrichia) ruralis, PPFD_95% 832 µmol m⁻² s⁻¹; (D) Marchantia polymorpha PPFD_95% 228 µmol m⁻² s⁻¹.