Cyathea delgadii Sternb. is a tree fern that grows in primary and secondary forests from Norhteastern to Southern Brazil. This study discusses the population structure and development of the sporophytic phase (caudex growth, frond production, phenology of spore production) of C. delgadii in a secondary forest in the State of Rio Grande do Sul, Brazil, based on observations of 41 plants during a 13 month period. The species had an aggregated spatial distribution pattern and higher frequency of smaller individuals, indicating high potential for population regeneration. On average, the caudex of plants grew 4.65 cm year-1, and the highest growth rates were recorded for taller plants. The similar frond production rate (5.75 fronds year-1) and senescence rate (4.92 fronds year¹) reflect the capacity to maintain a stable number of fronds. Only a few plants formed fertile fronds, while spore production and liberation occur in an asynchronous pattern.
tree ferns; ecology; spatial distribution; phenology; growth rate
