The Phenology of Osmunda claytoniana L. in Tataka area, Taiwan

The phenology of Osmunda claytoniana in Tataka area, Taiwan, including 38 plants of two populations, was investigated from April to October 2006. The processes of frond emergence, expansion, senescence, spore maturation and dispersion, and frond length were recorded. The results show that the fertile fronds emerged during late April and early May, whereas the sterile fronds emerged during May to late June. It took 25 to 45 days from frond emergence to full expansion. Spores matured in late May and mostly dispersed from late May to middle June. The numbers of fronds and average frond length of mature plants were significantly more than those of immature plants. The average frond length of the fertile fronds was not significantly higher than that of the sterile fronds. The growing season was from late April to October. The life span of fronds is 135 days in average. However, the pinnae bearing spores droop within 2 weeks after spore dispersed, whereas the other pinnae existed up to October.