Search

Background: The Rhynchosia totta complex is one of three taxonomically complicated African groups in the genus Rhynchosia. Numerous southern African species and infraspecific taxa (at least 19 names, 17 species and 2 varieties) have been described by various authors in the past, but were later reduced into synonymy with R. totta. Currently, only the typical variety is recognised in Southern Africa. Objectives: To investigate and update the circumscription of the taxa within the R. totta complex in southern Africa and to update their synonymies and distribution ranges. Methods: Specimens of R. totta at GRA, JRAU, K, NH and PRE were studied and compared, and measurements of characters recorded. Populations were also observed during field studies. Results: The examination of numerous specimens, as well as field investigations, has prompted the recognition of four varieties (one described here as new: R. totta var. longicalyx) and a new species (R. pedunculata) in southern Africa. Conclusions: A great variation in leaf structure and vestiture occurs within the R. totta complex, with the extreme forms easily recognisable. However, the total number of varieties are limited to four [R. totta vars. totta, longicalyx, rigidula and venulosa] and a new species described to accommodate specimens with a distinctly prostrate habit and upwardly directed leaves. [ABSTRACT FROM AUTHOR]

Crotalaria is a large genus of 702 species with its centre of diversity in tropical Africa and Madagascar and secondary radiations in other parts of the world. The current infrageneric classification system is based on morphological and morphomet-ric studies of the African taxa only and is here re-evaluated using a phylogenetic approach. DNA sequences derived from the nuclear ITS and the plastid matK, psbA-trnH and rbcLa markers were analyzed using parsimony and model-based (Bayesian) approaches. The resultant molecular phylogeny allowed for a new interpretation of diagnostically important morphological characters, including specialisations of the calyx, keel, standard petal and style, which are variously convergent in several unrelated infrageneric groups. Of particular interest is the congruence between the new phylogeny and the distribution of stand-ard petal callosity types. A sectional classification system for the entire genus is proposed for the first time. The new system that is formalised here comprises eleven sections: Amphitrichae, Calycinae, Crotalaria, Geniculatae, Glaucae, Grandiflorae, Hedriocarpae, Incanae, Schizostigma, Borealigeniculatae and Stipulosae. Sectional limits of the Geniculatae, Calycinae and Crotalaria are modified. The subsections Stipulosae, Glaucae and Incanae are raised to sectional level, while some groups previously recognized as subsections are abandoned due to non-monophyly (subsections Chrysocalycinae, Hedriocarpae, Macrostachyae and Tetralobocalyx). Two new sections are recognized, Amphitrichae and Borealigeniculatae. [ABSTRACT FROM AUTHOR]

Background Thesium L. is the largest genus in the family Santalaceae (sandalwood family). The last taxonomic revision of the southern African species dates back to 1925. An urgent revision of the genus is required as indicated in a recent national biosystematics research strategy for South Africa. Objectives To revise the Thesium confine species complex ( Thesium durum, T. confine and Thesium spartioides ) and to update the typification, nomenclature, descriptions and distribution ranges. Method Morphological characters were studied using own field collections as well as herbarium specimens from K, NU, PRE and PRU and images on Global Plants (JSTOR). Distribution ranges of the studied species were updated. Results An examination of morphological characters revealed great similarity between T. spartioides and T. confine. Both species have an herbaceous habit, decumbent growth form, terminal (or less frequently axillary) inflorescences and a sympatric northern distribution in South Africa. Thesium durum differs from T. spartioides and T. confine in having a shrubby habit, erect growth form and axillary inflorescences and occurs in the southern part of South Africa. Conclusion Thesium spartioides is synonymised under T. confine , and T. durum is retained as a separate species. [ABSTRACT FROM AUTHOR]

Many plant species representing the hemi-parasitic genus Thesium play important roles in communities around the globe as evidenced by the numerous ethnobotanical and contemporary uses, and pharmacological activities. However, no attempt has been made to amalgamate and analyze all of the available information. A comprehensive survey is needed to highlight knowledge gaps, as well as to determine the economic importance and commercial potential of the genus. To provide a comprehensive report on the species diversity, geographical distribution, ethnobotany, contemporary uses, chemistry, pharmacology and toxicology of the genus Thesium , as well as to give insights into possible future research opportunities. Literature on the ethnobotany, contemporary uses, chemistry and pharmacology of Thesium was gathered from standard search engines (Google, Google Scholar, PubMed, SciFinder and Scopus) using the phrase Thesium, as well as generic synonyms. Additional information came from relevant books, theses, patents and label information from herbarium specimens in the National Herbarium in Pretoria, South Africa. Information on geographical distributions was compiled from regional floras, regional revisions, original species descriptions and databases (GBIF, IPNI, Plants of the World online and The Plant List). Scientific names and synonyms were validated through www.plantsoftheworldonline.org. A total of 23 Thesium species, 17 from Africa and six from Asia, were found to have traditional and contemporary uses. Despite the near cosmopolitan distribution of the genus, no uses were recorded for Europe, Australia and North America. Thesium plants are most commonly used as medicines (18 species), functional foods and beverages (seven species), charms (six species) and crafts (three species), but also have several other minor uses. Charm uses were restricted to southern and East Africa, while several contemporary uses such as functional feeds and fodders, growth mediums and fertilizers and veterinary medicine were unique to Asia. Thesium chinense is by far the most utilized and versatile species with a total of 173 uses in nine use categories, followed by T. longifolium with 39 uses in six use categories. No specific trends were observed in the plant parts used. As a medicine Thesium is used to treat 137 ailments, predominantly reproductive and breast (22), respiratory tract (18), degenerative (11), digestive (11) and urinary (10) ailments. Chemical analyses are available for only eight species, with flavonoids, fatty acids and alkaloids as the main compounds. The potential influence of the host plants on the chemistry and pharmacology remains unexplored. The pharmacological activities of two species, T. chinense and T. viride, have been studied, while three other species are reported to be poisonous. Thesium chinense has analgesic, anti-inflammatory, anti-oxidation, chemopreventive, cytotoxic and other general therapeutic properties, and T. viride anti-bacterial activity. This study has highlighted the ethnobotanical, contemporary and pharmacological importance of Thesium and informed possible future research opportunities. While ample information is available on the traditional uses of the richly diverse African Thesium species, the few Asian species dominate the literature on contemporary uses and pharmacology, while relevant literature on species in the rest of the world is altogether lacking. In light of the popularity of Asian species as ingredients in contemporary medicines and products, further research is needed into African species and their uses, including potential commercial uses. As an important medicinal hemi-parasite in both Africa and Asia, the identities of ethnobotanically relevant species and their phytochemistry, pharmacology and toxicology remain underexplored and require more research attention. Image 1 • The global distribution pattern of all Thesium species (±350) is presented. • Of the 23 species with recorded uses, 18 have medicinal applications for 137 ailments. • Chemical compounds include flavonoids, fatty acids and alkaloids. • The flavonoids of one species are anti-inflammatory, analgesic and antibacterial. • The comprehensive database will guide future studies, especially of African species. [ABSTRACT FROM AUTHOR]