Crescimento do cáudice e fenologia de Dicksonia sellowiana Hook. (Dicksoniaceae) no sul do Brasil

Abstract

In Southern and Southeastern Brazil, the tree fern Dicksonia sellowiana Hook. still is illegally extracted from remnants forests for the use of its fibrous caudex cover, as well as for cultivation as an ornamental plant. In the present study the caudex growth, frond production, expansion and senescence as well as the formation and release of spores have been studied based on the observation of 37 plants. During an observation period of one year, the caudexes grew at an average of 5.65 cm year-1 and the growth rate presented a strong correlation with the height of the plants. Similar frond production rate (10.86 fronds year-1) and senescence (10.54 fronds year-1) evidenced the capacity of maintaining a stable number of fronds throughout the year. Only 14 individuals developed fertile fronds, most of them producing spores during the summer and liberating them during the winter. Production and release of spores were influenced more by temperature and photoperiod rather than by rainfall.