Plenckia populnea Reissek (1861: 29

Biral, Leonardo, 2020, New synonyms in Celastraceae toward an update of the flora of Brazil, Phytotaxa 446 (4), pp. 237-244 : 241

Plenckia populnea Reissek (1861: 29 , t. V, f. 3, 4, 5, t. X).

≡ Austroplenckia populnea (Reissek) Lundell (1939: 378) .

Type: Not designated.

= Plenckia bahiensis Loesener in Pilger (1923: 535-536). ≡ Austroplenckia bahiensis (Loes.) Lundell (1939: 378) . Type:— BRAZIL. Bahia: [West. Vacca Morta, Caatinga und Chapada mehr veredas, 650 m], November 1912, Zehntner 3061 (holotype, M [M0274921]!). syn. nov.

Plenckia bahiensis was described by Loesener (in Pilger 1923) from one collection gathered by the Swiss naturalist Leo Zehntner in the Brazilian state of Bahia. It is a neglected name absent in all the Celastraceae literature I examined after its publication. I found the holotype, indicated in the protologue as deposited in “Herb. Monac.” (Loesener in Pilger 1923: 536), among the undetermined Celastraceae specimens when visiting the herbarium M in November 2015. In the protologue, Loesener provides a Latin description and a short comment (in German) in that the new species is closely related to P. populnea but distinguished from it by shape and size of leaves and petioles. However, the author did not provide measures when comparing both species, and the differences are imprecise when a large amount of collections is examined. The size and shape of P. populnea leaves are extremely variable, as was mentioned in its description by Reissek (1861: 29) when he established five varieties based solely on leaf shape. The specimens of one of these varieties, P. populnea var. angustifolia Reissek (1861: 31) , were described as having elliptic, narrower leaves, and match those of P. bahiensis . Therefore, the recognition of P. bahiensis as a distinctive species from P. populnea is not supported.

When described Plenckia populnea, Reissek (1861: 29) designated several types (syntypes) for each one of the five varieties established by him. However, no specimen was cited or associated with the typical variety. In absence of a holotype, a lectotype is necessary to be designated (article 9.3. of the Shenzen Code, Turland et al. 2018). Additionally, as no isotype, syntypes, isosyntypes or paratypes exist, an uncited specimen or cited and uncited illustration, being part of the original material, must be chosen as lectotype (article 9.12. of the Shenzen Code, Turland et al. 2018). Thus, additional searches are necessary before any nomenclatural act involving the typification of Plenckia populnea , especially in the herbaria B, BR, M, LE and W, in order to find uncited specimens that comprise original material of the typical variety and can be designated as lectotype. If no specimen is found, the illustration on table X can be designated as lectotype.