In order for far‐red radiation at 760 nm to delay dark closing ofAlbizzia julibrissinpinnules, red light must be given simultaneously with or just prior to it. Studies have been made to determine whether a phytohormone can replace this red light requirement. Abscisic acid, gibberellin, kinetin, and indole‐3‐acetic acid have been found to replace the red light. Indole‐3‐carboxylic acid and a cytokinin antagonist are ineffective. In this hormone and far‐red interaction, all hormones are effective at μMor lower concentrations. The hormones show no interaction with red light at 660 nm. Simultaneous irradiation at 550 nm negates the effect of hormone and far‐red interaction in delaying leaflet closing. These results are additional evidence that an unidentified far‐red absorbing pigment could be involved with phytochrome in some far‐red