Updating the ionospheric propagation factor, M(3000)F2, global model using the neural network technique and relevant geophysical input parameters
- Oronsaye, Samuel Iyen Jeffrey
- Authors: Oronsaye, Samuel Iyen Jeffrey
- Date: 2013
- Subjects: Neural networks (Computer science) , Ionospheric radio wave propagation , Ionosphere , Geophysics , Ionosondes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5434 , http://hdl.handle.net/10962/d1001609 , Neural networks (Computer science) , Ionospheric radio wave propagation , Ionosphere , Geophysics , Ionosondes
- Description: This thesis presents an update to the ionospheric propagation factor, M(3000)F2, global empirical model developed by Oyeyemi et al. (2007) (NNO). An additional aim of this research was to produce the updated model in a form that could be used within the International Reference Ionosphere (IRI) global model without adding to the complexity of the IRI. M(3000)F2 is the highest frequency at which a radio signal can be received over a distance of 3000 km after reflection in the ionosphere. The study employed the artificial neural network (ANN) technique using relevant geophysical input parameters which are known to influence the M(3000)F2 parameter. Ionosonde data from 135 ionospheric stations globally, including a number of equatorial stations, were available for this work. M(3000)F2 hourly values from 1976 to 2008, spanning all periods of low and high solar activity were used for model development and verification. A preliminary investigation was first carried out using a relatively small dataset to determine the appropriate input parameters for global M(3000)F2 parameter modelling. Inputs representing diurnal variation, seasonal variation, solar variation, modified dip latitude, longitude and latitude were found to be the optimum parameters for modelling the diurnal and seasonal variations of the M(3000)F2 parameter both on a temporal and spatial basis. The outcome of the preliminary study was applied to the overall dataset to develop a comprehensive ANN M(3000)F2 model which displays a remarkable improvement over the NNO model as well as the IRI version. The model shows 7.11% and 3.85% improvement over the NNO model as well as 13.04% and 10.05% over the IRI M(3000)F2 model, around high and low solar activity periods respectively. A comparison of the diurnal structure of the ANN and the IRI predicted values reveal that the ANN model is more effective in representing the diurnal structure of the M(3000)F2 values than the IRI M(3000)F2 model. The capability of the ANN model in reproducing the seasonal variation pattern of the M(3000)F2 values at 00h00UT, 06h00UT, 12h00UT, and l8h00UT more appropriately than the IRI version is illustrated in this work. A significant result obtained in this study is the ability of the ANN model in improving the post-sunset predicted values of the M(3000)F2 parameter which is known to be problematic to the IRI M(3000)F2 model in the low-latitude and the equatorial regions. The final M(3000)F2 model provides for an improved equatorial prediction and a simplified input space that allows for easy incorporation into the IRI model.
- Full Text:
- Authors: Oronsaye, Samuel Iyen Jeffrey
- Date: 2013
- Subjects: Neural networks (Computer science) , Ionospheric radio wave propagation , Ionosphere , Geophysics , Ionosondes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5434 , http://hdl.handle.net/10962/d1001609 , Neural networks (Computer science) , Ionospheric radio wave propagation , Ionosphere , Geophysics , Ionosondes
- Description: This thesis presents an update to the ionospheric propagation factor, M(3000)F2, global empirical model developed by Oyeyemi et al. (2007) (NNO). An additional aim of this research was to produce the updated model in a form that could be used within the International Reference Ionosphere (IRI) global model without adding to the complexity of the IRI. M(3000)F2 is the highest frequency at which a radio signal can be received over a distance of 3000 km after reflection in the ionosphere. The study employed the artificial neural network (ANN) technique using relevant geophysical input parameters which are known to influence the M(3000)F2 parameter. Ionosonde data from 135 ionospheric stations globally, including a number of equatorial stations, were available for this work. M(3000)F2 hourly values from 1976 to 2008, spanning all periods of low and high solar activity were used for model development and verification. A preliminary investigation was first carried out using a relatively small dataset to determine the appropriate input parameters for global M(3000)F2 parameter modelling. Inputs representing diurnal variation, seasonal variation, solar variation, modified dip latitude, longitude and latitude were found to be the optimum parameters for modelling the diurnal and seasonal variations of the M(3000)F2 parameter both on a temporal and spatial basis. The outcome of the preliminary study was applied to the overall dataset to develop a comprehensive ANN M(3000)F2 model which displays a remarkable improvement over the NNO model as well as the IRI version. The model shows 7.11% and 3.85% improvement over the NNO model as well as 13.04% and 10.05% over the IRI M(3000)F2 model, around high and low solar activity periods respectively. A comparison of the diurnal structure of the ANN and the IRI predicted values reveal that the ANN model is more effective in representing the diurnal structure of the M(3000)F2 values than the IRI M(3000)F2 model. The capability of the ANN model in reproducing the seasonal variation pattern of the M(3000)F2 values at 00h00UT, 06h00UT, 12h00UT, and l8h00UT more appropriately than the IRI version is illustrated in this work. A significant result obtained in this study is the ability of the ANN model in improving the post-sunset predicted values of the M(3000)F2 parameter which is known to be problematic to the IRI M(3000)F2 model in the low-latitude and the equatorial regions. The final M(3000)F2 model provides for an improved equatorial prediction and a simplified input space that allows for easy incorporation into the IRI model.
- Full Text:
Studies on parasitoids of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), in South Africa
- Authors: Nofemela, Sicelo Robert
- Date: 2004
- Subjects: Plutellidae -- South Africa , Plutellidae -- Biological control , Plutellidae -- Parasites , Parasitoids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5780 , http://hdl.handle.net/10962/d1005468 , Plutellidae -- South Africa , Plutellidae -- Biological control , Plutellidae -- Parasites , Parasitoids
- Description: The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a major pest of Brassica crops in many parts of the world. Because of its ability to develop resistance to virtually all major groups of insecticides, including Bacillus thuringiensis Berliner (Bt), much attention has therefore been given to biological control using parasitoids. South Africa has an abundance of parasitoids attacking this pest. Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae) is the most abundant larval parasitoid of P. xylostella in South Africa. In East Africa, its role in biological control of P. xylostella is insignificant, and the most abundant parasitoid there is Diadegma mollipla (Holmgren) (Hymenoptera: Ichneumonidae), a larvalpupal parasitoid. In South Africa, however, D. mollipla is out-competed by C. plutellae. Total parasitism of P. xylostella in East Africa rarely exceeds 15%, therefore there is a need to introduce more effective and heat-tolerant parasitoids of P. xylostella to that region. This study was therefore initiated to examine the potential of C. plutellae and D. mollipla as biological control agents by studying certain aspects of their biology in the laboratory, as well as the suitability of C. plutellae for introduction into East Africa. Biological aspects studied were: (i) host instar preference, fecundity, and searching efficiency of C. plutellae and D. mollipla at different host and parasitoid densities; (ii) effects of temperature on parasitism of P. xylostella by C. plutellae and D. mollipla, and on their rates of development and emergence. In addition, the role of parasitoids in controlling P. xylostella on unsprayed cabbage plots was investigated. Both C. plutellae and D. mollipla preferred to attack second and third instar hosts than fourth instars in choice and no-choice tests. However, D. mollipla attacked more fourth instar hosts than C. plutellae. Cotesia plutellae laid mainly female eggs in second and third instar hosts than in fourth instars, whereas D. mollipla laid more female eggs in fourth instar hosts than in second and third instar hosts. Diadegma mollipla was more fecund [82.57 ± 32.87, (mean ± s.d.) than C. plutellae (42.13 ± 12.2), and was long lived (7.13 ± 3.69 days) compared to the latter (5.23 ± 2.7 days). An increase in host density resulted in the reduction in the area of discovery (a) and the killing power (K) for both parasitoids. No significant differences were detected between the searching efficiency (t = -1.42NS, d.f. = 48, P < 0.001) of the two parasitoids. An increase in parasitoid density also resulted in a decline in searching efficiency, but not the killing power, of both parasitoids. Cotesia plutellae completed development at all temperatures tested (21-33°C), whereas D. mollipla completed development at temperatures from 18-30°C, and C. plutellae had a lower threshold for development (8.14°C) compared to D. mollipla (10.23°C). At all tested temperatures, the generation time for C. plutellae was shorter compared to D. mollipla. The possible reasons for the dominance of C. plutellae over D. mollipla in the field are: shorter generation time, high production of female progeny in younger hosts, low interference among searching females, and relatively wide thermal tolerance. The role of parasitoids in regulating diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), populations was studied for two years (February 2000-January 2002) on unsprayed cabbage fields at Brits, North West Province, South Africa. Cabbage seedlings were transplanted in three consecutive times each year. Cabbage infestations by P. xylostella larvae and pupae, and their parasitoids, were monitored at weekly intervals. The flight activity of P. xylostella male moths was monitored using sex-pheromone traps. Trap catches indicated that the moths were active throughout the year. The flight activity of the moths corresponded with infestations on the crop. Trap catches and infestation levels were generally low from December to August and high from September to November. Eight hymenopteran parasitoids were reared: the larval parasitoids Cotesia plutellae (Kurdjumov) (Braconidae) and Apanteles halfordi (Ullyett) (Braconidae); the larval-pupal parasitoids Oomyzus sokolowskii (Kurdjumov) (Eulophidae) and Diadegma mollipla (Holmgren)(Ichneumonidae); the pupal parasitoid Diadromus collaris (Gravenhorst) (Ichneumonidae); and the hyperparasitoids Eurytoma sp. (Eurytomidae), Mesochorus sp. (Ichneumonidae), and Pteromalus sp. (Pteromalidae). Cotesia plutellae was the most abundant parasitoid of P. xylostella followed by O. sokolowskii, D. collaris, A. halfordi and D. mollipla. Parasitism of P. xylostella larvae was high reaching 100% on several occasions during late spring to end of autumn (November-May) each year. Parasitism was lower (<50%) in winter and early spring (June-September). Apanteles halfordi was absent in winter but re-appeared in spring. Parasitism of P. xylostella pupae by D. collaris was high only during spring (September-October). Hyperparasitism was generally low except when primary parasitoids were abundant in spring (September-November) and summer (December-February) when up to 25% of P. xylostella larvae and C. plutellae cocoons yielded hyperparasitoids. The role of other biotic and abiotic mortality factors on the population dynamics of P. xylostella is discussed.
- Full Text:
- Authors: Nofemela, Sicelo Robert
- Date: 2004
- Subjects: Plutellidae -- South Africa , Plutellidae -- Biological control , Plutellidae -- Parasites , Parasitoids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5780 , http://hdl.handle.net/10962/d1005468 , Plutellidae -- South Africa , Plutellidae -- Biological control , Plutellidae -- Parasites , Parasitoids
- Description: The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a major pest of Brassica crops in many parts of the world. Because of its ability to develop resistance to virtually all major groups of insecticides, including Bacillus thuringiensis Berliner (Bt), much attention has therefore been given to biological control using parasitoids. South Africa has an abundance of parasitoids attacking this pest. Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae) is the most abundant larval parasitoid of P. xylostella in South Africa. In East Africa, its role in biological control of P. xylostella is insignificant, and the most abundant parasitoid there is Diadegma mollipla (Holmgren) (Hymenoptera: Ichneumonidae), a larvalpupal parasitoid. In South Africa, however, D. mollipla is out-competed by C. plutellae. Total parasitism of P. xylostella in East Africa rarely exceeds 15%, therefore there is a need to introduce more effective and heat-tolerant parasitoids of P. xylostella to that region. This study was therefore initiated to examine the potential of C. plutellae and D. mollipla as biological control agents by studying certain aspects of their biology in the laboratory, as well as the suitability of C. plutellae for introduction into East Africa. Biological aspects studied were: (i) host instar preference, fecundity, and searching efficiency of C. plutellae and D. mollipla at different host and parasitoid densities; (ii) effects of temperature on parasitism of P. xylostella by C. plutellae and D. mollipla, and on their rates of development and emergence. In addition, the role of parasitoids in controlling P. xylostella on unsprayed cabbage plots was investigated. Both C. plutellae and D. mollipla preferred to attack second and third instar hosts than fourth instars in choice and no-choice tests. However, D. mollipla attacked more fourth instar hosts than C. plutellae. Cotesia plutellae laid mainly female eggs in second and third instar hosts than in fourth instars, whereas D. mollipla laid more female eggs in fourth instar hosts than in second and third instar hosts. Diadegma mollipla was more fecund [82.57 ± 32.87, (mean ± s.d.) than C. plutellae (42.13 ± 12.2), and was long lived (7.13 ± 3.69 days) compared to the latter (5.23 ± 2.7 days). An increase in host density resulted in the reduction in the area of discovery (a) and the killing power (K) for both parasitoids. No significant differences were detected between the searching efficiency (t = -1.42NS, d.f. = 48, P < 0.001) of the two parasitoids. An increase in parasitoid density also resulted in a decline in searching efficiency, but not the killing power, of both parasitoids. Cotesia plutellae completed development at all temperatures tested (21-33°C), whereas D. mollipla completed development at temperatures from 18-30°C, and C. plutellae had a lower threshold for development (8.14°C) compared to D. mollipla (10.23°C). At all tested temperatures, the generation time for C. plutellae was shorter compared to D. mollipla. The possible reasons for the dominance of C. plutellae over D. mollipla in the field are: shorter generation time, high production of female progeny in younger hosts, low interference among searching females, and relatively wide thermal tolerance. The role of parasitoids in regulating diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), populations was studied for two years (February 2000-January 2002) on unsprayed cabbage fields at Brits, North West Province, South Africa. Cabbage seedlings were transplanted in three consecutive times each year. Cabbage infestations by P. xylostella larvae and pupae, and their parasitoids, were monitored at weekly intervals. The flight activity of P. xylostella male moths was monitored using sex-pheromone traps. Trap catches indicated that the moths were active throughout the year. The flight activity of the moths corresponded with infestations on the crop. Trap catches and infestation levels were generally low from December to August and high from September to November. Eight hymenopteran parasitoids were reared: the larval parasitoids Cotesia plutellae (Kurdjumov) (Braconidae) and Apanteles halfordi (Ullyett) (Braconidae); the larval-pupal parasitoids Oomyzus sokolowskii (Kurdjumov) (Eulophidae) and Diadegma mollipla (Holmgren)(Ichneumonidae); the pupal parasitoid Diadromus collaris (Gravenhorst) (Ichneumonidae); and the hyperparasitoids Eurytoma sp. (Eurytomidae), Mesochorus sp. (Ichneumonidae), and Pteromalus sp. (Pteromalidae). Cotesia plutellae was the most abundant parasitoid of P. xylostella followed by O. sokolowskii, D. collaris, A. halfordi and D. mollipla. Parasitism of P. xylostella larvae was high reaching 100% on several occasions during late spring to end of autumn (November-May) each year. Parasitism was lower (<50%) in winter and early spring (June-September). Apanteles halfordi was absent in winter but re-appeared in spring. Parasitism of P. xylostella pupae by D. collaris was high only during spring (September-October). Hyperparasitism was generally low except when primary parasitoids were abundant in spring (September-November) and summer (December-February) when up to 25% of P. xylostella larvae and C. plutellae cocoons yielded hyperparasitoids. The role of other biotic and abiotic mortality factors on the population dynamics of P. xylostella is discussed.
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Research portfolio : environmental education
- Authors: Le Roux, Kim
- Date: 1999
- Subjects: Environmental education -- South Africa , Environmental education -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1738 , http://hdl.handle.net/10962/d1003622
- Full Text:
- Authors: Le Roux, Kim
- Date: 1999
- Subjects: Environmental education -- South Africa , Environmental education -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1738 , http://hdl.handle.net/10962/d1003622
- Full Text:
The development of an ecological model to determine flood release options for the management of the Phongolo floodplain in Kwazulu/Natal (South Africa)
- Authors: Weldrick, Sarah Katharine
- Date: 1996
- Subjects: Flood control -- Environmental aspects -- South Africa -- KwaZulu-Natal -- Pongolo floodplain , Fishes -- Behavior
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5258 , http://hdl.handle.net/10962/d1005102 , Flood control -- Environmental aspects -- South Africa -- KwaZulu-Natal -- Pongolo floodplain , Fishes -- Behavior
- Description: The Phongolo River floodplain in KwaZulu/Natal is a river-associated wetland which was subject to regular cycles of flooding in the past. The floods were associated with seasonal summer rainfall. Through the wet and dry cycles on the floodplain there was an alternation between the aquatic and terrestrial biomes. Many of the fishes on the floodplain are dependent on this cycle for their survival. The construction of the Pongolapoort Dam in 1969 has resulted in alterations to the timing, magnitudes and duration of the natural flooding events of the Phongolo River. This alteration has affected the fisheries. It is now necessary to simulate natural floods by artificial water releases from the dam. There are several demands on the water supply, so it has not always been possible to adhere to the natural flood regime. This necessitated the need for an integrated management programme to ensure the sustainability of the natural resources. A practical ecological model of the fishery was developed to determine an optimum flood release scenario for the floodplain. The relative abundances, distribution and species richness of the fishes were determined at various lakes and rivers on the floodplain. A community classification of the fishes was determined using TWINSPAN ordination. The potential yield of the fish at each site was calculated. Flood releases of varying magnitudes were simulated using Geographic Information Systems (GIS). This information was combined in a model which can be used by resource managers to estimate the percentage species compositions of fishes at each of the lakes, and to compare the actual harvest to the potential calculated sustainable yields of fishes for various flood release regimes. Subsistence agriculture and other beneficial ecological information can be incorporated into the model to determine the effect of different flood release options for the Phongolo floodplain.
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- Authors: Weldrick, Sarah Katharine
- Date: 1996
- Subjects: Flood control -- Environmental aspects -- South Africa -- KwaZulu-Natal -- Pongolo floodplain , Fishes -- Behavior
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5258 , http://hdl.handle.net/10962/d1005102 , Flood control -- Environmental aspects -- South Africa -- KwaZulu-Natal -- Pongolo floodplain , Fishes -- Behavior
- Description: The Phongolo River floodplain in KwaZulu/Natal is a river-associated wetland which was subject to regular cycles of flooding in the past. The floods were associated with seasonal summer rainfall. Through the wet and dry cycles on the floodplain there was an alternation between the aquatic and terrestrial biomes. Many of the fishes on the floodplain are dependent on this cycle for their survival. The construction of the Pongolapoort Dam in 1969 has resulted in alterations to the timing, magnitudes and duration of the natural flooding events of the Phongolo River. This alteration has affected the fisheries. It is now necessary to simulate natural floods by artificial water releases from the dam. There are several demands on the water supply, so it has not always been possible to adhere to the natural flood regime. This necessitated the need for an integrated management programme to ensure the sustainability of the natural resources. A practical ecological model of the fishery was developed to determine an optimum flood release scenario for the floodplain. The relative abundances, distribution and species richness of the fishes were determined at various lakes and rivers on the floodplain. A community classification of the fishes was determined using TWINSPAN ordination. The potential yield of the fish at each site was calculated. Flood releases of varying magnitudes were simulated using Geographic Information Systems (GIS). This information was combined in a model which can be used by resource managers to estimate the percentage species compositions of fishes at each of the lakes, and to compare the actual harvest to the potential calculated sustainable yields of fishes for various flood release regimes. Subsistence agriculture and other beneficial ecological information can be incorporated into the model to determine the effect of different flood release options for the Phongolo floodplain.
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Sex ratios of Coccophagus atratus compere (Hymenoptera:Aphelinidae) in relation to host availability
- Authors: Donaldson, John Sydney
- Date: 1985
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5632 , http://hdl.handle.net/10962/d1004933
- Description: The mode of sex determination in most Hymenoptera is that of arrhenotokous parthenogenesis, i.e. females originate from fertilised eggs and males develop parthenogenetically from unfertilised ones. Females can therefore determine the sex of each of their offspring by controlling fertilisation. This has led to much speculation about the factors that govern hymenopteran sex ratios. Many sex ratio theories predict that solitary Hymenoptera should produce male and female offspring in a ratio of 1:1. The limited data available on sex ratios in solitary Hymenoptera does not support this prediction. However, for various reasons, data may not be representative and few detailed studies have been done. The purpose of this study was, therefore, to examine sex ratios of Coccophagus atratus, a solitary hymenopteran parasitoid, to determine whether sex ratios in this species approach 1: 1. C. atratus is a suitable species for sex ratio studies because male and female eggs are deposited in different hosts. The sex of deposited eggs can, therefore, be determined at oviposition. This eliminates any possible effects of differential mortality. Laboratory experiments were designed to determine whether C. atratus females deposit male and female eggs in fixed proportions or in a set sequence. In addition, samples of hosts were collected from the field to assess C. atratus sex ratios under natural conditions. Results show that C. atratus females do not produce sex ratios that approach 1:1 and male and female eggs are not deposited in a set sequence. Sex ratios are variable and appear to be related to the relative abundance of hosts suitable for female development and for male development. These results are discussed in relation to current sex ratio theories.
- Full Text:
Sex ratios of Coccophagus atratus compere (Hymenoptera:Aphelinidae) in relation to host availability
- Authors: Donaldson, John Sydney
- Date: 1985
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5632 , http://hdl.handle.net/10962/d1004933
- Description: The mode of sex determination in most Hymenoptera is that of arrhenotokous parthenogenesis, i.e. females originate from fertilised eggs and males develop parthenogenetically from unfertilised ones. Females can therefore determine the sex of each of their offspring by controlling fertilisation. This has led to much speculation about the factors that govern hymenopteran sex ratios. Many sex ratio theories predict that solitary Hymenoptera should produce male and female offspring in a ratio of 1:1. The limited data available on sex ratios in solitary Hymenoptera does not support this prediction. However, for various reasons, data may not be representative and few detailed studies have been done. The purpose of this study was, therefore, to examine sex ratios of Coccophagus atratus, a solitary hymenopteran parasitoid, to determine whether sex ratios in this species approach 1: 1. C. atratus is a suitable species for sex ratio studies because male and female eggs are deposited in different hosts. The sex of deposited eggs can, therefore, be determined at oviposition. This eliminates any possible effects of differential mortality. Laboratory experiments were designed to determine whether C. atratus females deposit male and female eggs in fixed proportions or in a set sequence. In addition, samples of hosts were collected from the field to assess C. atratus sex ratios under natural conditions. Results show that C. atratus females do not produce sex ratios that approach 1:1 and male and female eggs are not deposited in a set sequence. Sex ratios are variable and appear to be related to the relative abundance of hosts suitable for female development and for male development. These results are discussed in relation to current sex ratio theories.
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A revision of the genus fockea endl. (Asclepiadaceae)
- Authors: Court, Doreen
- Date: 1982 , 2013-04-10
- Subjects: Asclepiadaceae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4242 , http://hdl.handle.net/10962/d1007072 , Asclepiadaceae
- Description: A taxonomic revision of Fockea Endl. (Asclepiadaceae) is presented in which 5 species are recognised. Descriptions, illustrations and a key to the species are provided. F. comaru (E. Mey.)N.E.Br. is presented sensu lato, and because of its earlier publication in 1838 takes priority over F. angustifolia K. Schum. which was described in 1893. Historical and ecological notes on the genus are given and phylogenetic conclusions drawn. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
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- Authors: Court, Doreen
- Date: 1982 , 2013-04-10
- Subjects: Asclepiadaceae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4242 , http://hdl.handle.net/10962/d1007072 , Asclepiadaceae
- Description: A taxonomic revision of Fockea Endl. (Asclepiadaceae) is presented in which 5 species are recognised. Descriptions, illustrations and a key to the species are provided. F. comaru (E. Mey.)N.E.Br. is presented sensu lato, and because of its earlier publication in 1838 takes priority over F. angustifolia K. Schum. which was described in 1893. Historical and ecological notes on the genus are given and phylogenetic conclusions drawn. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
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