Aeschynanthus `Koral' plants were grown in photoperiods of 8 to 14 hr (8 hr natural daylight plus 0-6 hr incandescent light of 3 μmolm-2s-1) beginning January, March, or June. The number of weeks to anthesis and number of leaves on shoots reaching anthesis were not affected by photoperiod, but differed when treatments began. Number of shoots reaching anthesis per plant was greatest in photoperiods of 13 hr for treatments beginning January or June. Time of year influenced flowering more than photoperiod, suggesting a temperature interaction. A. `Koral' plants were given photoperiods of 12 or 24 hr (daylight fluorescent lamps at 100 or 50 μmolm-2s-1 respectively) at temperatures of 18 or 24 C. After 8 weeks, 18 C plants had fewer nodes before the first flower bud than 24 C plants. Number of nodes to the first flower bud was decreased under the 24 hr treatments at 24 C, while no difference to photoperiod was observed at 18 C. Flowering of A. `Koral' appears to be promoted by 18 C temperature where the plant behaves as a day neutral plant. At 24 C, A. `Koral' responds as a long day plant.