Abstract

Seeds of Pieris floribunda (Pursh ex Sims) Benth. and Hook, (mountain andromeda) were germinated at 25°C (77°F) or an 8/16 hr thermoperiod of 25°/15°C (77°/59°F) with daily photoperiods of 0, ½, ½ twice daily, 1, 2, 4, 8, 12, or 24 hr. In seeds exposed to light, germination at 25°C (77°F) began between 3 and 6 days compared to 6 to 9 days at 25°/15°C (77°/59°F), but the delay did not influence cumulative germination. For seeds exposed to light, 30-day germination for equivalent photoperiods at both temperatures was similar. Without light, 30-day germination at 25°C (77°F) and 25°/15°C (77°/59°F) was 38% and 52%, respectively. Daily photoperiods as short as ½ hr increased cumulative germination to 90% at 25°C (77°F) and 25°/15°C (77°/59°F). The remaining light treatments yielded 88 to 95% germination. High germination percentages were due in part to rigorous seed grading prior to initiation of the study.