Evidence of primary hemiepiphytism in Pleopeltis bradeorum (Polypodiaceae)

Primary hemiepiphytism was documented in Pleopeltis bradeorum (Polypodiaceae) at the La Selva Biological Station, Heredia, Costa Rica. Multiple sporophytes and gametophytes were observed, photographed, and collected. Gametophytes were found on the trunks of trees and lianas within 2.5 m of the ground. Mature sporophytes with fertile fronds were observed growing ca. 2.5 m above the ground with feeder roots descending to the soil. Additional sterile mature sporophytes were observed ca. 4 m up, on small- and medium-sized branches; though these individuals did not appear to be connected to the ground by roots; that is, they were holoepiphytic. Our findings indicate that P. bradeorum conforms to many of the features characteristic of primary hemiepiphytic ferns. Corresponding to expectation, sporophytes exhibited long-creeping, dorsiventrally flattened rhizomes with dimorphic clasping and feeder roots. The clasping and feeder roots, however, were not strongly differentiated as in other primary hemiepiphytic ferns. Gametophytes departed from expectation by having a cordate thallus. The life history and habit of P. bradeorum documented here indicates that it is both a primary hemiepiphyte and holoepiphyte.