Thesium schmiedeliae (Santalaceae), a new species from Knersvlakte quartz fields, South Africa

Abstract

SummaryWe test the hypothesis that the Thesium (Santalaceae) collection previously known as Thesium sp. D.A.Zhigila & A.M.Muasya 1006 is new to science. We formally describe and name it T. schmiedeliae. The new species is an erect to suberect shrublet, c. 20 cm tall, glaucous in overall appearance, with stems terete in transverse section, and leaves bracts, and bracteoles succulent. Molecular and morphological data support the placement of T. schmiedeliae in subgenus Frisea section Annulata. The new species is endemic to the Knersvlakte Nature Reserve and occurs in the edaphically unique quartz islands. Thesium schmiedeliae is preliminarily assessed for conservation purposes as Vulnerable as it is threatened by drought, severe fragmentation of its quartz-field habitat, small population size, and a small area of occupancy.