LAUSR

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.