I came across an interesting plant called honeysweet at dvplants.com:
At the bottom of the entry page it says:
honeysweet is a C4 plant and that it "has one of the highest rates of photosynthesis ever recorded."
Interesting and so what does that mean?
Contrasted to C3 photosynthesis, the C4 photosynthetic pathway is more efficient based on resistance to photorespiration which is a wasteful process. Unlike in C3 photosynthesis, the initial CO2-fixing enzyme PEPcase in C4 cycle does not act as oxygenase and therefore it does not fix O2 even when it is in high concentration within the cell.
So, in a nutshell, C4 photosynthesis is just more efficient than other forms of photosynthesis.
Examples of C4 species are the economically important crops corn or maize (Zea mays), sugarcane (Saccharum officinarum), sorghum (Sorghum bicolor), and millets, as well as the switchgrass (Panicum virganum) which has been utilized as a source of biofuel.
https://www.cropsreview.com/c4-plants.html