Marlothistella is a genus of flowering plants belonging to the family Aizoaceae. It is endemic to the Cape Provinces of South Africa. The genus name of Marlothistella is in honour of Rudolf Marloth (1855–1931), a German-born South African botanist, pharmacist and analytical chemist.

Marlothistella uniondalensis is a South African endemic perennial sub-tuberous shrubby species found in the Western Cape province growing in grasslands or karroid vegetation. The specific epithet uniondalensis refers to Uniondale, a small town in the Little Karoo, where the species is found. It is a small succulent mesemb with thick taproots and long, narrow, grey-green leaves that can grow up to 15cm tall. It forms several branching taproots that form a caudex-like structure, which can reach up to 8cm in diameter. The leaves grow up to 4.5cm long and are cylindrical at the base and sharply pointed at the top. During the winter months, the plant produces stunning flowers with narrow petals ranging from white and pale pink to magenta.