Browsing by Author "Boatwright, James"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    A taxonomic revision of the twelve-scaled species of struthiola (thymelaeaceae: thymelaeoideae): the struthiolamundiig roup
    (Elsevier, 2025) Boatwright, James; Makhoba, Thuli; Magee, Anthony Richard
    Struthiola L. (Thymelaeaceae: Thymelaeoideae) is a genus of approximately 40 species (Wright, 1915; manning and goldblatt, 2012) largely endemic to South Africa, but with four species in tropical Africa (Peterson, 1958, 1978, 2006). the Greater Cape Floristic Region (GCFR) is the centre of diversity for the genus, as well as for several other related southern African Thymelaeoideae, including Gnidial., Lachnaea l. and Passerina l. Almost all of the South African species of Struthiola are restricted to the GCFR (manning and goldblatt, 2012; Snijman, 2013), with only three of the South African species occurring beyond the region in the grasslands of KwaZulu-Natal (Wright, 1915; hilliard and burtt, 1986; Hilliard, 1993). Struthiola l. was established by Linnaeus (1767) in his Systema Naturae ed. 12 for two species of Thymelaeaceae that were characterised by flowers with just four anthers and petaloid scales (incorrectly described as nectary glands) and subsequently conserved against the earlier name Belvala Adans. (1763) with the conserved type S. erecta l. The genus was last revised more than a century ago by Wright (1915), and as the taxonomy of the southern African species remains poorly understood it has been identified as one of the priority groups for taxonomic revision (Victor et al., 2015; Victor, 2020). Meisner (1857), in his global treatment of Thymelaeaceae, subdivided the genus into three morphological groups based on the number of petaloid scales in the mouth of the hypanthium, viz. four, eight or 12. All subsequent authors have retained these informal subdivisions. The molecular analyses by Makhoba (2024) recovered the species with four scales (the Struthiola striata group) and those with 12 scales (the Struthiola mundii group) as two independent clades nested within the remaining species of the genus, all with eight scales. This confirms the value of the putatively derived scale-numbers of four and 12 in identifying relationships in the genus. The four-scaled S. striata group was recently revised (Makhoba et al., 2019) as a first step towards a comprehensive revision of the genus. As the next step we present a revision of the twelve-scaled species comprising the S. mundii group. Twelve species and three varieties were recognized in the S. mundii group at the onset of this study. Characters such as habit, flower colour, presence or absence of hairs on the hypanthium, hypanthium length, shape of the petaloid scales and the colour of the associated hairs, bracteole length, and presence or absence
  • Thumbnail Image
    Item
    Impacts and control of alien Proteaceae invasion in the Western Cape Province, South Africa
    (University of the Western Cape, 2017) Erckie, Laimi Nelago Koskima; Boatwright, James
    Research focused on ecological impacts and control of invasive alien species (IAS) is gaining attention worldwide. The eradication and control of invasive alien plants (IAP) is essential for the restoration of native plant communities. Understanding ecological impacts and potential invasive risks of IAP is important for their effective management, particularly for prioritisation. Most studies concerning impacts on vegetation structure and plant-pollinator interactions have measured few ecological metrics, resulting in a superficial understanding of plant species invasion. Additionally, most studies related to the control of IAP have focused on major invaders which have demonstrated severe impacts, with less focus on emerging invaders. This study assessed ecological impacts, invasive risks and chemical control options for alien Hakea drupacea and Banksia species in the Western Cape Province, South Africa. Multiple ecological metrics data on vegetation, soil and plant-pollinator parameters were measured and compared between invaded and uninvaded sites. The invasion risk of fourteen Banksia species which have been introduced to South Africa was evaluated by conducting a weed risk assessment (WRA). The herbicide efficacy of resprouting Banksia integrifolia and Banksia serrata was determined by rating plants response to different treatments, with percentage, height and resprout vigour as measures. Results revealed significant negative impacts of alien H. drupacea and Banksia speciosa invasion on native plant species richness and diversity and on the abundance of native pollinators. The study demonstrated that 79% of Banksia species have a high risk of invading the Fynbos Biome. Chemical control with triclopyr+picloram mix provided effective means of controlling resprouting Banksia species. The high invasive risk of Banksia species and competitive effects of invasive alien B. speciosa and H. drupacea with native plant species for biotic and abiotic resources represents a major threat to biodiversity conservation in the Fynbos Biome. The removal of both naturalised and invasive alien H. drupacea and Banksia populations is recommended in order to conserve native plant communities in the Fynbos Biome.
  • Thumbnail Image
    Item
    Neuroprotective activities of crossyne flava bulbs and amaryllidaceae alkaloids: Implications for parkinson’s disease
    (Molecules, 2021) Omoruyi, Sylvester; Ibrakaw, Abobaker; Ekpo, Okobi; Boatwright, James
    Parkinson’s disease (PD) is one of the most common neurodegenerative diseases and affects approximately 6.3 million people worldwide. To date, the treatment of PD remains a challenge, as available treatment options are known to be associated with serious side effects; hence, the search for new treatment strategies is critical. Extracts from the Amaryllidaceae plant family as well as their alkaloids have been reported to have neuroprotective potentials. This study, therefore, investigated the biological activities of Crossyne flava and its isolated alkaloids in an in vitro MPP+ (1-methyl-4- phenylpyridinium) PD model using SH-SY5Y cells. The effects of the total extract as well as the four compounds isolated from Crossyne flava (i.e., pancratinine B (1), bufanidrine (2), buphanisine (3), and epibuphanisine (4)) were evaluated for cell viability, neuroprotection, levels of reactive oxygen species (ROS), adenosine triphosphate activity (ATP), and caspase 3/7 activity in SH-SY5Y cells. The results obtained showed that pre-treatment with both the extract and the isolated compounds was effective in protecting the SH-SY5Y cells from MPP+-induced neurotoxicity and inhibited ROS generation, ATP depletion as well as apoptosis induction in the SH-SY5Y cells. The results of this study show that the Amaryllidaceae plant family may be a source of novel compounds for the treatment of neurodegenerative diseases, which validates the reported traditional uses.
  • Thumbnail Image
    Item
    Systematics of subtribe Anthosperminae and the generic affinities of Anthospermum and Nenax (Rubiaceae: Anthospermeae)
    (University of Western Cape, 2021) Nemando, Rangani; Boatwright, James
    The last taxonomic treatment of the subtribe Anthosperminae was in 1986 by Puff., nevertheless, few attempts have been made to resolve the phylogeny and the inter- and infrageneric relationships within the subtribe. The genera Anthospermum L. (39 species) and Nenax Gaertn. (11 species) are considered the most difficult groups to distinguish. Anthospermum species are widely distributed in Sub-Saharaan Africa and Madagascar with the highest concentration of taxa in southern Africa, while Nenax species are restricted in southern Africa, south-western Cape Floristic Region. The two genera share common morphological and anatomical characters.
  • Thumbnail Image
    Item
    Taxonomy and invasive potential of the Cassiinae in southern Africa (Caesalpinioideae, Fabaceae)
    (University of the Western Cape, 2019) Liada, Musandiwa; Boatwright, James
    Cassiinae is a large subtribe of the tribe Cassieae (Caesalpinioideae) that comprises ca. 700 species distributed throughout the Americas, Africa, Eurasia and Australia. The southern African species of Cassiinae (indigenous, naturalised and cultivated) were all treated under Cassia L. in Gordon-Gray’s (1977) treatment for the Flora of southern Africa. However, given the subsequent generic recircumscriptions in the subtribe and the expansion of collections of these taxa since, this treatment is now outdated. The aim of the present study was to provide an overview of the subtribe Cassiinae in southern Africa, assess the invasive potential of all naturalized species (viz. Cassia s.s., and Senna Mill.) and conduct a detailed taxonomic revision of the species of Chamaecrista (L.) Moench. indigenous to southern Africa.