Variation in floral induction requirements of Hibiscus sp.

Thirty-six Hibiscus L. species were grown for 20 weeks under three lighting treatments at 15, 20, or 25 +/- 1.5 degreesC air temperature to identify f lowering requirements for each species. In addition, species were subjectiv ely evaluated to identify those species with potential ornamental significa nce based on flower characteristics and plant form. Lighting treatments wer e 9 hour ambient light(St. Paul, Mim., November to May, 45 degreesN), ambie nt light plus a night interruption using incandescent:lamps (2 mu mol.m(-2) .s(-1); 2200 to 0200 HR), or ambientlight plus 24-hour supplemental lightin g from high-pressure sodium lamps (100 mu mol.m(-1).s(-1)). Five day-neutra l, six obligate short-day, six facultative short-day, three obligate long-d ay, and one facultative long-day species were identified. Fifteen species d id not flower. Temperature and lighting treatments interacted to affect lea f number below the first flower and/or flower diameter on same species. Hib iscus acetosella Welw. ex Hiern, H. cisplatinus St.-Hil., H. radiatus Cav., and H. trionum L. were selected as potential new commercially significant ornamental species.