Celtis holtzii Engler (1915: 12, in obs.).

Holotype: —[illustration] AFRICA. “Kome Kavagango, Muanza, Victoria Nyansa”, without date, fr., Fig. 6 E page 13 in Veg. Erde [ Engler] 9(3,1) (1915).

Epitype (designated here): — AFRICA. Tanganyika [currently Tanzania], 13 April 1905, fr., Dr. Holtz 1591 (epitype B barcode 10 0057838!) .

Nomenclatural notes: —When describing C. holtzii, Engler (1915) cited figure 6E, but did not provide details of any herbarium specimens. Polhill (1964) and Sattarian et al. (2006) cited the Holtz 1591 specimen deposited in B as a “ holotype ”. However, this material cannot be recognized as the holotype, because it was not used by Engler (1915) and therefore should not be considered original material (ICN Art. 9.4). We here recognize the illustration in Engler (1915) as the holotype for C. holtzii, as it is the only original material (ICN Art. 9.4). In addition to the holotype, we designate the specimen by Holtz 1591 (B barcode 10 0057838) as epitype of C. holtzii (ICN Art. 9.9), because Engler’s (1915) illustration is ambiguous, which may lead to doubts about the identity of the species. We assign an epitype, because in Celtis many species share vegetative characteristics, making identification doubtful (see the article by Chamorro et al. 2021). Currently C. holtzii is a synonym of C. africana, the latter species is characterized by the indumentum on the leaf surfaces, and this feature was not illustrated in Engler’s (1915) protologue, which reinforces the need for an epitype.

Taxonomic notes: —Synonym of C. africana (Sattarian et al. 2006) .