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Polyploid speciation in the Greater Cape Floristic Region : species limits within Ehrhara calycina
Ehrharta calycina J. E. Sm. (Poaceae) is a widespread and often abundant species whose core distribution lies within the Greater Cape Floristic Region (GCFR). Importantly, it shows a high degree of morphological and ploidy level variation. Based on observations of distinct forms co-occurring at mult...
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| Format: | Thesis |
| Language: | English |
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Department of Biological Sciences
2015
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| _version_ | 1867613225324904448 |
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| access_status_str | Open Access |
| author | Musker, Seth |
| author2 | Verboom, Tony |
| author_browse | Musker, Seth Verboom, Tony |
| author_facet | Verboom, Tony Musker, Seth |
| author_sort | Musker, Seth |
| collection | Thesis |
| description | Ehrharta calycina J. E. Sm. (Poaceae) is a widespread and often abundant species whose core distribution lies within the Greater Cape Floristic Region (GCFR). Importantly, it shows a high degree of morphological and ploidy level variation. Based on observations of distinct forms co-occurring at multiple sites, the hypothesis that E. calycina comprises more than one species was tested. Morphological analysis of herbarium specimens using a multivariate approach found strong evidence for the presence of two distinct phenetic clusters among specimens from sites of sympatry, and these were termed ‘robust’ and ‘slender’ forms. This translated to a broader sampling of specimens from across the GCFR (n = 516), of which over 91% could be attributed to one or other form with >90% confidence using linear discriminant analysis. Importantly, chromosome counts supported the hypothesis that these phenetic clusters represent distinct cytotypes, with slender forms being diploid (n = 12) and robust forms tetraploid (n = 24), thus providing the primary reproductive isolating mechanism between the forms. Furthermore, differences in climatic niche suggest that these forms represent ecologically independent entities. Finally, evidence that the forms differ in palatability has considerable practical implications given that E. calycina is regarded as having high pasture value. Together, our results provide multiple lines of evidence for the existence of at least two morphologically distinct, reproductively isolated species within E. calycina, and suggest that the role of polyploidy in generating floral diversity in the GCFR may be more important than previously thought. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/14016 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:45.765Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2015 |
| publishDateRange | 2015 |
| publishDateSort | 2015 |
| publisher | Department of Biological Sciences |
| publisherStr | Department of Biological Sciences |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/14016 Polyploid speciation in the Greater Cape Floristic Region : species limits within Ehrhara calycina Musker, Seth Verboom, Tony Biological Sciences Ehrharta calycina J. E. Sm. (Poaceae) is a widespread and often abundant species whose core distribution lies within the Greater Cape Floristic Region (GCFR). Importantly, it shows a high degree of morphological and ploidy level variation. Based on observations of distinct forms co-occurring at multiple sites, the hypothesis that E. calycina comprises more than one species was tested. Morphological analysis of herbarium specimens using a multivariate approach found strong evidence for the presence of two distinct phenetic clusters among specimens from sites of sympatry, and these were termed ‘robust’ and ‘slender’ forms. This translated to a broader sampling of specimens from across the GCFR (n = 516), of which over 91% could be attributed to one or other form with >90% confidence using linear discriminant analysis. Importantly, chromosome counts supported the hypothesis that these phenetic clusters represent distinct cytotypes, with slender forms being diploid (n = 12) and robust forms tetraploid (n = 24), thus providing the primary reproductive isolating mechanism between the forms. Furthermore, differences in climatic niche suggest that these forms represent ecologically independent entities. Finally, evidence that the forms differ in palatability has considerable practical implications given that E. calycina is regarded as having high pasture value. Together, our results provide multiple lines of evidence for the existence of at least two morphologically distinct, reproductively isolated species within E. calycina, and suggest that the role of polyploidy in generating floral diversity in the GCFR may be more important than previously thought. 2015-09-15T10:32:54Z 2015-09-15T10:32:54Z 2013 Bachelor Thesis Honours BSc (Hons) http://hdl.handle.net/11427/14016 eng application/pdf Department of Biological Sciences Faculty of Science University of Cape Town |
| spellingShingle | Biological Sciences Musker, Seth Polyploid speciation in the Greater Cape Floristic Region : species limits within Ehrhara calycina |
| thesis_degree_str | Bachelor's / Honours |
| title | Polyploid speciation in the Greater Cape Floristic Region : species limits within Ehrhara calycina |
| title_full | Polyploid speciation in the Greater Cape Floristic Region : species limits within Ehrhara calycina |
| title_fullStr | Polyploid speciation in the Greater Cape Floristic Region : species limits within Ehrhara calycina |
| title_full_unstemmed | Polyploid speciation in the Greater Cape Floristic Region : species limits within Ehrhara calycina |
| title_short | Polyploid speciation in the Greater Cape Floristic Region : species limits within Ehrhara calycina |
| title_sort | polyploid speciation in the greater cape floristic region species limits within ehrhara calycina |
| topic | Biological Sciences |
| url | http://hdl.handle.net/11427/14016 |
| work_keys_str_mv | AT muskerseth polyploidspeciationinthegreatercapefloristicregionspecieslimitswithinehrharacalycina |