Hemi-epiphytism in Vandenboschia collariata (Hymenophyllaceae)
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Abstract
Hemi-epiphytism represents an evolutionarily important yet poorly understood growth habit in ferns. Anatomy and ontogeny related to hemi-epiphytism in the fern Vandenboschia collariata (Hymenophyllaceae) were investigated at La Selva Biological Station, Costa Rica. Multiple specimens representing all stages of gametophyte and sporophyte growth were observed in the field, collected, and examined in the laboratory. Cross sections of sporophyte roots and stems were made by hand, and examined using light microscopy. Sporophytes were found to initiate growth on the base of trees up to ca. 25 cm above the ground. Two types of stems were produced: 1) a short stem that produces crowded roots, and 2) one or more climbing stems that branch from the short stem, climb up the trunk, and produce distant leaves but no roots. This study presents the first description of gametophytes in V. collariata and clarifies ontogeny and anatomy related to the hemi-epiphytic growth habit in ferns.
Keywords
Costa Rica fern gametophyte hemi-epiphyte Hymenophyllaceae La Selva Biological Station Trichomanes VandenboschiaNotes
Acknowledgments
The authors are grateful to Robbin Moran and Matt Ogburn for guidance and comments on the manuscript. This project was conceived in January 2008 during the Tropical Ferns and Lycophtes course sponsored by the Organization for Tropical Studies (OTS). Fieldwork was conducted with the assistance of a post-course grant from OTS.
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