Browsing by Author "Francis, Caitlynne Melanie"

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    Phylogenetic inference and macro-evolutionary patterns in Ficinia Schrad. (Cyperaceae)
    (2009) Francis, Caitlynne Melanie; Muasya, A Muthama
    The genus Ficinia Schrad. has its centre of diversity in the Cape Floristic Region and phylogenetic relationships within this genus have not been fully studied representing a gap in the body of work on the Cyperaceae. Phylogenetic analyses provide strong support for the sister relationship between Isolepis and Ficinia in both parsimony and Bayesian analyses (BP = 96; PP = 1). Isolepis marginata consistently resolved as more closely related to the Ficinia clade than to the rest of the species in Isolepis. Ficinia undosa was positioned outside its own genus (as well as the entire FiciniaIsolepis clade) rendering the genus paraphyletic. This species appears to be more closely related to members of the Scirpus falsus-Scoipoides clade. As in previous studies, the New Zealand monotypic genus Desmoschoenus is resolved as a member of Ficinia and is closely allied with Ficinia pallens (BP=43, PP=0.56). Macroevolutionary reconstruction of characters such as life form and the presence of a gynophore disk revealed interesting patterns within the genus as well. Perennial habit is a synapomorphy for Ficinia and distinguishes it from the generally annual sistergenus Isolepis. Though a young genus when compared with Isolepis, Ficinia has radiated in the CFR quite rapidly following the -shift toward Mediterranean climate in this region. While support across the tree is quite low, due perhaps to the slow mutation rate among recent and rapidly radiated perennials, several relationships within m the genus are resolved with moderate nodal support.
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    Systematics of the Laurencia complex (Rhodomelaceae, Rhodophyta) in southern Africa
    (2014) Francis, Caitlynne Melanie; Bolton, John J; Anderson, Robert J; Mattio, Lydiane
    The diversity, systematics and distribution of the red algal Laurencia complex (Rhodomelaceae, Rhodophyta) of South Africa were investigated, being generally poorly understood and taxonomically understudied. Prior to this study, ten currently recognised species in the Laurencia complex were recorded from South Africa: all were ascribed to the genus Laurencia J.V. Lamouroux (Laurencia sensu stricto). However, the diversity anddistribution of the complex in South Africa, and the larger South Western Indian Ocean (SWIO), have not yet been reassessed following the numerous taxonomic changes in this group published over the last two decades. The taxonomy, phylogeny and biogeography of the Laurencia complex in South Africa and apart of the SWIO were reassessed by examining external morphology, vegetative anatomy(including corps en cerise counts) and analysing the plastid-encoded rbcL gene sequence data of recent collections. The collection encompassed more than 250 specimens, were primarily from the coastline of South Africa and to a lesser extent from Madagascar, Mozambique, Reunion, Mauritius and the Europa and Glorioso Islands in the SWIO. In addition, a few new collections were included from Western Australia and Japan. The genetic analyses were done under Bayesian inference using the GTR + I + G model, from which phylogenetic hypotheses were deduced and pairwise sequence divergences were calculated.
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    Taxonomy and phylogeny of the South African Plocamium species Rhodophyta, Plocamiaceae
    (2009) Francis, Caitlynne Melanie; Bolton, John J; Mandiwana-Neudani, Tshifhiwa Gift; Anderson, Robert J
    A number of taxonomic accounts have been produced for species of the red alga Plocamium in South Africa and the rest of the world; yet, the use of phylogenetic analyses to understand relationships within the genus has only been incorporated in the last decade in Japan and Europe. We used morphological and DNA sequence characters (ITSJ-5.8S-ITS2) in both independent and combined Bayesian and parsimony analyses to investigate the relationships within South African Plocamium species and between South African Plocamium species and those from elsewhere. South African Plocamium forms a monophyletic group within the genus, and Plocamium is paraphyletic with respect to Plocamiocolax, the other genus in the family Plocamiaceae. The morphological and molecular phylogenies are incongruent; morphologically relationships resolve poorly toward the tips and several of the sister relationships resolved on the basis of the nuclear ITS marker are questionable. The results of this study revealed that phylogenetic relationships within Plocamium in South Africa are highly complex and particularly when evaluated in the context of the genus worldwide. The worldwide taxonomy of the genus is in need of full revision as this and several recent studies have highlighted incongruencies in the previous morphological taxonomic accounts of the genus.