Farrar, Donald .
The peculiar reproductive biology of Woodwardia areolata.
WOODWARDIA areolata is a common fern of the southeastern US occurring on moist acidic soils and on sandstone bluffs. To the north of its principal range it occurs as isolated colonies. Because many of these have been found within the last few decades, the species has been thought to be actively colonizing more northern habitats. We studied the northern occurrences in Missouri, Illinois, and Indiana in a conservation assessment for the National Forest Service, Region 9. Allelic diversity in W. areolata is extremely low and sporophyte production by gametophytes grown in isolation is very high, both as might be expected in a colonizing species. However, evidence of ongoing sexual reproduction is non-existent in most northern sites and most colonies appear to be clones derived from a single founding spore. Assuming they are clones, most are older than thought, many 50 to 100 years, and correlate with times of timber harvests, mining activities, or other major disturbances. A possible reason for absence of greater sexual reproduction and limited ongoing migration is the failure of the indusium to open and release spores from fertile fronds.[c.e.:srb]
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1 - Iowa State University, Department of Ecology, Evolution & Organismal Biology, 253 Bessey Hall, Ames, Iowa, 50011-1020, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 31st, 2006
Time: 4:30 PM