A taxonomic revision of the genus Bergeranthus Schwantes (Mesembryanthemaceae) in South Africa
- Authors: Dold, Anthony P
- Date: 2002
- Subjects: Aizoaceae -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4248 , http://hdl.handle.net/10962/d1007481 , Aizoaceae -- South Africa
- Description: The genus Bergeranthus Schwantes comprises ten species ofleaf-succulent Mesembryanthemaceae that are centred in the Albany centre of endemism and restricted to the Eastern Cape Province of South Africa. No taxonomic revision of the genus, or key to the species of Bergeranthus, has been undertaken since its description by Schwantes in 1926. The species concepts are mostly based on single, or at best severaL cultivated plants and are notoriously narrow and in some cases incorrect. Louisa Bolus described five of the ten currently recognized species of Bergeranthus (as well as B. cookii, B.firmus, B. glenensis, B.jamesii, and B. longisepalus) from cultivated plants that she had never seen in the wild. This narrow species concept, compounded by morphological change that occurs in response to environmental factors, presents an assemblage of ill-defmed and poorly known taxa that have been prioritised for taxonomic attention by various authors. Furthermore, the generic delimitation of Bergeranthus with the closely related genera Rhombophyllum and Hereroa is unclear and requires attention before generic revisions are attempted for all three genera. The taxonomic revision presented here is based on a study of 210 wild populations of Bergeranthus as well as cultivated representatives of these and 135 herbarium specimens. A phenetic analysis based on 36 vegetative characters was initially used to delimit taxa. Thereafter sixty-three macro- and micro-morphological characters were critically assessed for the purposes of species delimitation, amendment of existing species descriptions and the description of two new species. Macromorphological characters examined included rootstock, leaf(36), inflorescence, floral (nine), fruit (nine), seed germination and seedling characters. Micro-morphological characters examined included leaf anatomy, leaf epidermal wax layer, anther shape and point of adherence, pollen and seed characters. This revision reduces two species into synonymy and two new species, B. albomarginatus and B. nanus, are described. Existing species descriptions are improved and all species are illustrated. A key to species is provided. The reproductive biology, ecology, phytogeography and distribution data of the genus are discussed towards an improved understanding of the genus. The generic delimitation of Bergeranthus and its closest relatives, Rhombophyllum and Hereroa, are discussed based on an examination of 25 morphological characters and two phenological characters and a provisional key to genera is provided. A phylogenetic analysis of all 10 species of Bergeranthus, both species of Rhombophyllum and a single species of Hereroa (H. granulata) was undertaken to support species and generic delimitation.
- Full Text:
- Date Issued: 2002
- Authors: Dold, Anthony P
- Date: 2002
- Subjects: Aizoaceae -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4248 , http://hdl.handle.net/10962/d1007481 , Aizoaceae -- South Africa
- Description: The genus Bergeranthus Schwantes comprises ten species ofleaf-succulent Mesembryanthemaceae that are centred in the Albany centre of endemism and restricted to the Eastern Cape Province of South Africa. No taxonomic revision of the genus, or key to the species of Bergeranthus, has been undertaken since its description by Schwantes in 1926. The species concepts are mostly based on single, or at best severaL cultivated plants and are notoriously narrow and in some cases incorrect. Louisa Bolus described five of the ten currently recognized species of Bergeranthus (as well as B. cookii, B.firmus, B. glenensis, B.jamesii, and B. longisepalus) from cultivated plants that she had never seen in the wild. This narrow species concept, compounded by morphological change that occurs in response to environmental factors, presents an assemblage of ill-defmed and poorly known taxa that have been prioritised for taxonomic attention by various authors. Furthermore, the generic delimitation of Bergeranthus with the closely related genera Rhombophyllum and Hereroa is unclear and requires attention before generic revisions are attempted for all three genera. The taxonomic revision presented here is based on a study of 210 wild populations of Bergeranthus as well as cultivated representatives of these and 135 herbarium specimens. A phenetic analysis based on 36 vegetative characters was initially used to delimit taxa. Thereafter sixty-three macro- and micro-morphological characters were critically assessed for the purposes of species delimitation, amendment of existing species descriptions and the description of two new species. Macromorphological characters examined included rootstock, leaf(36), inflorescence, floral (nine), fruit (nine), seed germination and seedling characters. Micro-morphological characters examined included leaf anatomy, leaf epidermal wax layer, anther shape and point of adherence, pollen and seed characters. This revision reduces two species into synonymy and two new species, B. albomarginatus and B. nanus, are described. Existing species descriptions are improved and all species are illustrated. A key to species is provided. The reproductive biology, ecology, phytogeography and distribution data of the genus are discussed towards an improved understanding of the genus. The generic delimitation of Bergeranthus and its closest relatives, Rhombophyllum and Hereroa, are discussed based on an examination of 25 morphological characters and two phenological characters and a provisional key to genera is provided. A phylogenetic analysis of all 10 species of Bergeranthus, both species of Rhombophyllum and a single species of Hereroa (H. granulata) was undertaken to support species and generic delimitation.
- Full Text:
- Date Issued: 2002
The trade in medicinal plants in the Eastern Cape Province, South Africa
- Dold, Anthony P, Cocks, Michelle L
- Authors: Dold, Anthony P , Cocks, Michelle L
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6512 , http://hdl.handle.net/10962/d1005940
- Description: A study of the trade in medicinal plants in the Eastern Cape Province of South Africa undertook to document the species traded, to determine the quantities harvested annually, and to assess the economic value of the trade. All the participants involved at the different levels of the trade were included in the survey, that is, informal street hawkers, owners of amayeza esiXhosa stores, traditional healers, and consumers of traditional medicines. In total, 282 questionnaires were administered in six urban centres. It was found that poorly educated black middle-aged women of low economic standing dominate the trade. A minimum of 166 medicinal plant species were traded at the study sites alone, providing 525 tonnes of plant material valued at approximately R27 million annually. Plants were harvested from a diverse range of vegetation types including Valley Thicket, Afromontane Forest, Coastal Forest and Moist Upland Grassland, the most frequently sold species differing significantly from those documented in similar studies in other regions. The Forest Biome was the vegetation type found to be most threatened by over-harvesting. Of the species documented, 93% were being harvested unsustainably and 34 species have been prioritised for conservation management.
- Full Text:
- Date Issued: 2002
- Authors: Dold, Anthony P , Cocks, Michelle L
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6512 , http://hdl.handle.net/10962/d1005940
- Description: A study of the trade in medicinal plants in the Eastern Cape Province of South Africa undertook to document the species traded, to determine the quantities harvested annually, and to assess the economic value of the trade. All the participants involved at the different levels of the trade were included in the survey, that is, informal street hawkers, owners of amayeza esiXhosa stores, traditional healers, and consumers of traditional medicines. In total, 282 questionnaires were administered in six urban centres. It was found that poorly educated black middle-aged women of low economic standing dominate the trade. A minimum of 166 medicinal plant species were traded at the study sites alone, providing 525 tonnes of plant material valued at approximately R27 million annually. Plants were harvested from a diverse range of vegetation types including Valley Thicket, Afromontane Forest, Coastal Forest and Moist Upland Grassland, the most frequently sold species differing significantly from those documented in similar studies in other regions. The Forest Biome was the vegetation type found to be most threatened by over-harvesting. Of the species documented, 93% were being harvested unsustainably and 34 species have been prioritised for conservation management.
- Full Text:
- Date Issued: 2002
- «
- ‹
- 1
- ›
- »