(3126) Proposal to reject the name <i>Mimosa monjollo</i> ( <i>Enterolobium monjollo</i> ) ( <i>Fabaceae</i> )

(3126) Mimosa monjollo Vell., Fl. Flumin. Icon. 11: t. 26. 29 Oct 1831 [Angiosp.: Legum.], nom. utique rej. prop. Lectotypus (hic designatus): [icon ined.] “Polyg. Monoec. MIMOSA monjollo Tab. 26” (Divisão de Manuscritos, Bibliot. Nac., Rio de Janeiro, No. mss1198660_030 [photo!]). Martius published the combination Enterolobium monjollo (Vell.) Mart. (in Flora 20(2, Beibl.): 117. 1837, ‘mongollo’), based on Mimosa monjollo Vell., validly published by Vellozo (Fl. Flumin. Icon. 11: t. 26. 1831) solely by an illustration with analysis (Madrid ICN Art. 38.9, 38.10; Turland & al. in Regnum Veg. 162. 2025). As with other names from Florae Fluminensis, original herbarium specimens of M. monjollo are not known to exist. The only original material is therefore the illustration. The published plate (t. 26) in Florae Fluminensis was prepared long after Vellozo's death in 1811 (Blake, Diccion. Bibliogr. Brazil. 5: 64. 1899), but traces to an original drawing now deposited at Biblioteca Nacional do Rio de Janeiro that was directly available to Vellozo. Nevertheless, under Art. 9.4(d, e) both of these illustrations constitute original material available for lectotypification. The absence of any herbarium specimen identified by Martius (l.c.) with Enterolobium monjollo suggests that he was uncertain about the correct application of the name. As a result, the practical use of this name began only much more recently, dating from the 1980s. The earliest known specimens identified as E. monjollo are likely RB00160830, RB00160838, and RB00160847, identified by H.C. de Lima in 1984, as well as RB00160803, RB00160819, and IAN 100135, all identified by Mesquita in November 1986. It is therefore possible that the widespread and consolidated use of the name E. monjollo originated from these herbarium identifications, particularly following Mesquita's (1990) master's thesis (Revis. Tax. Gên. Enterolobium Mart. (Mimosoideae) Reg. Neotrop. [Univ. Fed. Rural Pernambuco]). Thus, Mesquita (l.c. 1990), in his attempt to conceptualize the basionym Mimosa monjollo, which had previously been known only from its illustration in Florae Fluminensis, based his work on the illustration and description published much later in Vellozo (Fl. Flumin. [in Arq. Mus. Nac. Rio de Janeiro 5]: 436. 1881), on the characteristics of herbarium specimens, and on a plant cultivated in the arboretum of the Rio de Janeiro Botanical Garden. However, some of the characteristics used by Mesquita (l.c. 1990) to define E. monjollo differ markedly from Vellozo's original illustration. The main discrepancy concerns the number of leaflets: Mesquita described 6 to 11 pairs per pinna, while the illustration clearly shows 8 to 33 pairs—a considerably higher number. In addition, the fruit in the illustration depicts various stages of development, culminating in a complete coil, in contrast with Mesquita's description of only a half coil. Therefore, the morphological evidence indicates that the name was misapplied, and we conclude that E. monjollo, as recognized by Mesquita, does not correspond to the same species depicted in Florae Fluminensis. Is Mimosa monjollo Vell. the same as Robrichia glaziovii (Benth.) A.R.M. Luz & E.R. Souza (in Syst. Bot. 47: 274. 2022; based on Enterolobium schomburgkii var. glaziovii Benth. in Martius, Fl. Bras. 15(2): 458. 1876; ≡ E. glaziovii (Benth.) Mesquita in Acta Bot. Brasil. 7(2): 18. 1993)? Despite the contrasting number of both pinnae and leaflets per pinna, 3–7 pairs of pinnae and 8–33 pairs of leaflets per pinna in the illustration (Vellozo, l.c. 1831: t. 26) of M. monjollo vs. 20–30 pairs of pinnae with 40–80 pairs of leaflets in Robrichia glaziovii (Mesquita, l.c. 1993: 18), this latter species appears to best match Vellozo's concept. Robrichia glaziovii is characterized primarily by its twisted fruits reaching 1.5 coils, the rough texture of the epicarp surface, and a petiole with a villous-ferruginous indumentum (Mendes & al. in Flora e Funga do Brasil. 2025, accessed 4 Sep 2025). The latter two are diagnostic features distinguishing it from its closest relative, Robrichia schomburgkii (Benth.) A.R.M. Luz & E.R. Souza (l.c.: 276; based on Pithecellobium schomburgkii Benth. in London J. Bot. 3: 219. 1844). In addition, Robrichia glaziovii has a geographical distribution restricted to the Atlantic Forest in the states of Bahia, Espírito Santo, Minas Gerais, and Rio de Janeiro (Mendes & al., l.c.), which matches both the current distribution of the species now called E. monjollo (Morim & al. in Flora e Funga do Brasil. 2025, accessed 4 Sep 2025) and the potential original distribution of M. monjollo (“Offendi silvis mediterraneis ad ripas fluvii Parahyba”, Vellozo, l.c. 1881). Thus, considering the combination of traits such as the high number of leaflets, the presence of twisted fruits with a rough surface, the presence of trichomes on the petiole, and the shared geographic distribution, a provisional placement in R. glaziovii remains the most plausible identification for M. monjollo, with the epithet of the latter name being available and having priority over that of the former in Robrichia (Barneby & J.W. Grimes) A.R.M. Luz & E.R. Souza (l.c.: 274; based on Enterolobium sect. Robrichia Barneby & J.W. Grimes in Mem. New York Bot. Gard. 74(1): 249. 1996). Although conserving the name Enterolobium monjollo by designating a conserved type to match its recent usage would be a possible nomenclatural remedy, Vellozo's original name lacks extant type material and is associated with an ambiguous illustration, which would complicate the safe application of his epithet. Moreover, Lima's and Mesquita's misapplication of “E. monjollo” in specimen annotations is relatively recent (1984, 1986) and not yet widely established in herbaria, with other misapplied names still competing for use due to the underlying taxonomic problems in this group. For these reasons, we have opted to name and describe the taxon to which this name has been misapplied as a new species and provide a clear taxonomic treatment for it. We therefore propose the formal rejection of the name Mimosa monjollo Vell., pursuant to Art. 56.1, since its continued acceptance would cause nomenclatural instability and require the replacement of the names Enterolobium glaziovii or Robrichia glaziovii widely used in scientific literature, in genus reviews, and floristic inventories (e.g., Luz & Souza, l.c. 2022; Mendes & al., l.c. 2025). This paper is part of the Ph.D. thesis by HFM at the Programa de Pós-Graduação em Biologia de Fungos, Algas e Plantas of Universidade Federal de Santa Catarina. HFM is grateful for the financial support from CAPES via a doctoral scholarship grant (88887.821398/2023-00). JP and JFBP thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPq (Proc. n. 307931/2021-8, 304082/2023-6, respectively) for the financial support. LPQ research in Legume Systematics is supported by CNPq (Process 305230/2021-2) and UEFS/FINAPESQ (grant 045/2023).