The dispute over whether Welwitschia does or does not use this process was resolved by finding that it does but only in an extremely small amount. Unusually for aquatic plants, the quillworts of the genus Isoetes carry out this process to reduce competition with other aquatic plants. Leaf thickness positively correlates with this process’s prevalence. Recent studies have refuted the long-accepted claim that this process is particularly common among (*) epiphytes. (-5[1])This process leads to the storage of large amounts of malic acid in vacuoles. (-5[2])This process causes the stomata to be open only at night to reduce water loss during the day, (0[1]-5[1])so it is especially common in desert plants, such as cacti. For 10 points, name this pathway that temporally separates the two parts of photosynthesis, a rarer alternative to C3 and C4. ■END■ (10[2])