Four flowering plant species described from Katanga (Democratic Republic of the Congo) are based on specimens collected in Guangxi, China

The original set of botanical collections of the agronomist H.A. Homblé is conserved in the herbarium BR. Homblé was one of the first collectors (1911–1913) for the flora of Katanga, Democratic Republic of the Congo. Many Homblé specimens were described as taxonomic novelties; 107 tropical African plant species are named after him. Before his colonial career in Katanga, Homblé stayed about two years (1909–1911) in Guangxi, China. His incompletely labelled Chinese collections were erroneously considered as collected in Katanga. This supposed African origin has led to confusion with regard to the identification, and even resulted in the description of four species believed to be new for science. This paper presents and discusses Homblé's collection made in Guangxi, and the assumed novelties in it. Drosera insolita is a synonym of the Asian Drosera lunata, widespread from India to Australia. Three other species are new synonyms.Caesalpinia homblei is a synonym of the pantropical Caesalpinia bonduc. Digitaria polybotryoides is a synonym of Digitaria abludens, a widespread species in tropical Asia. Grewia katangensis is the only species that proved to be synonymous with an endemic species, Grewia cuspidatoserrata, only known from S Yunnan, and here reported as a new record for Guangxi. Lysimachia candida and Impatiens chinensis should be deleted from the list of the Congo Flora. The importance of careful specimen labelling and label interpretation is discussed.