Total vegetative hydrocarbon composition of sicklepod ( Cassia obtusifolia L.) changed with age and photoperiod. Leaf epicuticular hydrocarbon composition of sicklepod and coffee senna ( Cassia occidentalis L.) were different in plants of equal age grown in 16-hr or 12–13-hr photoperiods. The major leaf epicuticular hydrocarbon constituent of sicklepod grown in a 16-hr photoperiod was an unsaturated C 32 constituent with a molecular weight of 446 with subsidiary constituents at relative elution temperatures equivalent to C 30 and C 34 having 34·9, 8·7, and 6·8% respectively, of the total hydrocarbon content.