Bryological and Lichenological Section/ABLS
Harbaugh, Danica T. .
Loss of dispersability on islands? An example from the tropical moss Syrrhopodon confertus (Calymperaceae).
In his book, Island Biology, Carlquist (1974) theorized that vascular plants tend to become more asexual as you move further away from the mainland and onto isolated oceanic islands. The acrocarpous, dioecious moss Syrrhopodon confertus (Calymperaceae) is widespread across the paleotropics, ranging from Australia, to New Guinea and across to the South Pacific islands of Polynesia; this distribution offers a unique opportunity to test the hypothesis that mosses also exhibit a loss of dispersability on islands, by favoring asexual over sexual reproduction. For 28 specimens of S. confertus from diverse localities across the South Pacific and Australia, I scored the presence or absence of gemmae (vegetative propagules), and counted the number of sporophytes and gametangia on 15 randomly selected stems from each specimen. No gemmae or sporophytes had been reported in the literature, however both were observed occasionally in this study. Results demonstrate that S. confertus has fewer gametangia and sporophytes on islands than the mainland, with no spore production evident on the most remote islands. These results suggest that there has been a loss of sexual reproduction on islands, possibly due to selection for reduced dispersability.
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1 - National Museum of Natural History, Smithsonian Institution, Botany, P.O. Box 37012, MRC 166, Washington, DC, 20013-7012, USA
Syrrhopodon confertus .
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Magpie B/Cliff Lodge - Level B
Date: Monday, July 27th, 2009
Time: 8:45 AM