To estimate how the transfer of water, oxygen, and carbon dioxide might be affected by leaf water deficit, we should know how the leaf geometry depends on water status. To study this relationship, I measured the length, width, total volume, and air space volume of leaf pieces in the relative water content range from 1.0 to about 0.65. For each experiment, 40 similar rectangular leaf pieces about 28 X 32 mm were cut from mature, fully turgid leaflets (soybean) or larger leaf pieces (maize), which had been floating on