Nomenclatural notes on southern African Oxalis species

In 1860, Sonder described the species Oxalis minima Sond. based on the specimen Zeyher 237 (Sonder 1860:312). This was an illegitimate later homonym, as the combination was already published for three other species of Oxalis, namely by Steudel (1821:579), by Don (1831:760) and by Ecklon and Zeyher (1835:92). Kuntze (1891:91) moved several Oxalis species to the genus Acetosella Kuntze. As the epithet ‘minima’ had already been assigned to one of the older species [Acetosella minima (Eckl. & Zeyh.) Kuntze = O. minima Eckl. & Zeyh.], Kuntze (1891:91) published a nomen novum for O. minima Sond., namely Acetosella sonderiana Kuntze. Knuth (1930:355) again treated all species under the genus Oxalis and lists this taxon as O. minima Sond. Macbride (1934:8) recognised that O. minima Sond. was an illegitimate superfluous name and corrected the name for the South African species while dealing with the South American O. minima G.Don. In doing this, Macbride (1934:8) unfortunately used an orthographical variant of the epithet and proposed the name Oxalis sonderana (Kuntze) J.F.Macbr. instead of ‘sonderiana’. Two years later, Salter (1936:155) described a variety of this taxon as Oxalis minima Sond. var. alba T.M.Salter. Salter (1944) later revised the southern African members of Oxalis, including the taxon based on the Zeyher 237 type specimen. At some point between 1936 and the revision, he became aware that the original species epithet was preoccupied, and in Salter (1944:196), he thus superfluously proposed the name Oxalis sonderiana (Kuntze) T.M.Salter (an isonym) for this species. He appears to have been unaware of the publication by Macbride (1934), as he does not refer to it in his section entitled ‘Previous Systematic Work’ (Salter 1944:9).

The work of Salter (1944) has been widely accepted.For this reason, most South African databases [including those of the South African National Biodiversity Institute (SANBI), namely the Botanical Database of Southern Africa (BODATSA; www.newposa.sanbi.org)and the Red List of South African Plants (www.redlist.sanbi.org)],as well as the international database Tropicos (www.tropicos.org),list (or had listed, see below) this species with Salter as final author.In contrast, the International Plant Names Index (IPNI; www.ipni.org)recognises the publication by Macbride (1934:8) and thus correctly lists the species as Oxalis sonderiana (Kuntze) J.F.Macbr.This confusion is further exacerbated by notes to the effect that Macbride (1934:8) should be the author rather than Salter (1944:196) on the type specimen in Kew and yet it is listed as O. sonderiana (Kuntze) T.M.Salter in the Kew herbarium catalogue.In addition, an accession listed as Oxalis minima Sond.(collection Schlechter 7931, barcode K000419342!) on the same herbarium sheet is not this species, but is still Background: The correct author citation of Oxalis sonderiana (Kuntze) J.F.Macbr.and the validity and identity of the species Oxalis beneprotecta R.Knuth, Oxalis bullulata T.M.Salter and Oxalis pulchella Jacq.var.beneprotecta (R.Knuth) T.M.Salter are unclear.
Objectives: To resolve the nomenclatural and taxonomic confusion surrounding these four taxa.

Method:
We studied relevant herbarium records (especially type material) of all the taxa, and paired this with scrutiny of all publications that bear reference to the nomenclature and taxonomy of these species.

Results:
The correct author citation for Oxalis sonderiana has been determined; Oxalis bullulata is confirmed as a distinct species, and the continued recognition of Oxalis beneprotecta as a variety of Oxalis pulchella is suggested.It is further ascertained that the name 'Oxalis nidulans Turcz.' is not a later homonym, but a reference to a misapplication of Oxalis nidulans Eckl.& Zeyh. to the type specimen of Oxalis sonderiana.

Conclusion:
These results clarify the current confusion surrounding these taxa in global herbaria and in national and international databases.

Nomenclatural notes on southern African
Oxalis species

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listed as an accession of O. sonderiana (Kuntze) T.M. Salter. Salter (1944:198)  This means that the orthographical variant published by Macbride (1934:8) is to be treated as an error to be automatically corrected and, therefore, the publication by Macbride (1934:8) should be accepted as the first valid publication of the combination, given that it predates that of Salter (1944:196) 1985).A note on the sheet of Zeyher 237 at S indicates that it came from the Sonder Herbarium.We therefore choose this sheet as lectotype.Our choice is further supported by the fact that this specimen is well preserved and includes many flowering individuals.Unfortunately, this specimen does not contain bulb material, but it still represents the best material available as lectotype, with copies available in various international herbaria, including SAM.

Identity of Oxalis beneprotecta and Oxalis bullulata
A He viewed it as a distinct species primarily because of the very different bulb -Oxalis bullulata has a small bulb (half to a third the length of the bulb of O. pulchella) with a characteristic puckered appearance to the tunics (to which the epithet 'bullulata' refers).Both O. pulchella var.beneprotecta and O. bullulata were maintained in the Salter (1944:151, 164) monograph on Oxalis, and there is no question that he considered these entirely separate entities.Schreiber (1966:5;1967:296) revised the Namibian species of Oxalis and rejected the taxonomic placements by Salter (1936:49) Acetosella sonderianaKuntze in Revis.Gen.Pl.1: 91 (1891); Oxalis nidulans auct.sensuTurcz.in Bull.Soc.Imp.Nat.Mosc.31,2:436 (1858), non Eckl.& Zeyh.(1836); Oxalis minima Sond. in Fl.Cap.1: 336 (1860), nom.illegit.non Steud.(1821), nec G.Don (1831), nec Eckl.& Zeyh.(1835); ['O.sonderiana (Kuntze) T.M.Salter' in J. S. Afr.Bot., Suppl.vol.Salter (1944:198) specifically states that the type of O. sonderiana (Zeyher 237) is in the Sonder Herbarium.The first set of the South African collections made by Ecklon & Zeyher was acquired by Sonder.After Sonder's death, his herbarium was sold in several parts, the most important of which are currently housed at S and MEL.S houses the South African set of Ecklon & Zeyher specimens (Stafleu & Cowan Sonder (1860) author citation for the species is thus Oxalis sonderiana (Kuntze) J.F.Macbr., as listed in IPNI and recently corrected in BODATSA.Sonder (1860:20*, in a list of Addenda and Corrigenda) seems to be the first to cite the name 'O. nidulans, Turcz.Bull.Mosc.1858.No.2, p. 436' as a synonym of O. minima.McBride  (1934:8)andSalter (1944:196)both list this name in synonymy, probably merely followingSonder (1860)and not referring to the original publication, as the Russian journal in which the article by Turczaninow (1858) was published would likely not have been easily available to them.Because of these publications, it is generally accepted, and also listed as such on IPNI, that the name 'O. nidulans Turcz.' is a later homonym.However, Turczaninow did not publish a new name, but specifically accredits the name to Ecklon & Zeyher.He lists Zeyher 237 as being representative and mentions the following about the specimens in his herbarium: not use the term 'type' or equivalent, nor does he provide explanation in this article that the specimens mentioned should be treated as types(Art.7.10,McNeill et al. 2012).AsEcklon and Zeyher (1835:92)earlier cited a single collection from 'Pampoenekraal' in the protologue, this specimen (Ecklon & Zeyher 724) is the holotype of O. nidulans.Oxalis sonderiana (Kuntze) J.F.Macbr. in Candollea 6: 8 (1934), as 'sonderana'; Note: . She accepted O. beneprotecta as a good taxon at species level and synonymised O. bullulata and O. parvicormus under this species.Having examined three isotypes of O. bullulata, Schreiber (1966:5) further stated her certainty that O. bullulata is identical to O. beneprotecta and therefore synonymised the former under the latter, despite the demonstrable morphological differences.Despite acknowledging that she had never seen Salter's Namaqualand specimens of O. bullulata, and stating that they may not belong to O. beneprotecta, Schreiber (1967:296) nevertheless still listed them under O. beneprotecta.These taxonomic changes were accepted in the List of Species of Southern African Plants by Gibbs Russel et al. (1987:99), from where they were propagated to many databases, both in South Africa (BODATSA and the Red List of South African Plants) and internationally (e.g.Tropicos).The sheet of the holotype at B has been wrongly encoded on www.plants.jstor.orgas Dinter 5162.The sheet at SAM has been wrongly encoded as Dinter 5782. Note: