(3128) Proposal to conserve the name <i>Eucalyptus largiflorens</i> ( <i>Myrtaceae</i> ) against <i>E. bicolor</i>

(3128) Eucalyptus largiflorens F. Muell. in Trans. & Proc. Vict. Inst. Advancem. Sci. 1: 34. 1855 [Angiosp.: Myrt.], nom. cons. prop. Typus: Australia, South Australia, Murray River, above Moorundie, 1 Feb 1851, Mueller (MEL barcode MEL 10392). (=) Eucalyptus bicolor A. Cunn. ex T. Mitch., J. Exped. Trop. Australia: 390. 16 Feb–31 Mar 1848, nom. rej. prop. Lectotypus (hic designatus): Australia, “Sub-Tropical New Holland”, 20 Nov 1846, Mitchell 439 (CGE barcode CGE00065086; isolectotypus: K barcode K000347558). The name Eucalyptus largiflorens F. Muell. (in Trans. & Proc. Vict. Inst. Advancem. Sci. 1: 34. 1855) is today widely accepted for a species that is widespread along the Murray-Darling Rivers Basin including southern Queensland, New South Wales, Victoria and eastern South Australia (Chippendale in Fl. Australia 19: 384. 1988; Slee & al., EUCLID: Eucalypts of Australia, ed. 4. 2020, accessed 8 Sep 2025; Hill in PlantNET: New South Wales Flora online, accessed 8 Sep 2025; Brooker & Slee in VicFlora: Flora of Victoria online, accessed 8 Sep 2025), often being defined as a community dominant. Mueller's protologue consists of a detailed diagnosis enumerating various morphological characters (bark, leaves, buds, flowers and fruits) such that there is no ambiguity over what entity he is describing. A collection of Mueller at MEL (barcode MEL 10392) from along the Murray River was designated by Willis (in Muelleria 1: 166. 1967) as lectotype, as this was one of the four localities mentioned by Mueller (l.c. 1855). The name Eucalyptus bicolor A. Cunn. ex T.L. Mitch. (J. Exped. Trop. Australia: 390. 1848) appears in the body of Mitchell's text as a manuscript name attributed to Allan Cunningham. Mitchell (l.c.) writes “the Eucalyptus bicolor A. Cunn. MS., a species closely allied to E. haematomma [sic] Sm., but the marginal nerve is not so close to the edge of the leaf (this is the ‘bastard box’ of the carpenters)”. The protologue is scant, and while it compares it to another species, the differentiating character is not one that could be used to circumscribe a species. Other new species names mentioned on the same page are given full Latin descriptions as footnotes (i.e.: Sida tuberosa Hook. = Abutilon tuberosum (Hook.) Walp. and Eucalyptus acuminata Hook. = E. camaldulensis subsp. acuta Brooker & M.W. McDonald). There are two specimens that are regarded as original material for E. bicolor: a Kew (K) specimen (barcode K000347558) bears leaves and open flowers while a Cambridge University Herbarium (CGE) specimen (barcode CGE00065086) has leaves, flower buds, as well as open flowers, and can be confidently identified as E. largiflorens. The opercula present on the CGE specimen help to confirm that it belongs to the same species as the type of E. largiflorens. Mueller (in J. Proc. Linn. Soc., Bot. 3: 90. 1858) and Bentham (Fl. Austral. 3: 214–215. 1867) considered the publication of Eucalyptus bicolor valid and the latter treated E. largiflorens in synonymy. Maiden, when examining the material at CGE, made the annotation “nomen nudum” in 1901. However, he later changed his mind and considered the name validly published (Crit. Revis. Eucalyptus 2: 6–13. 1910, 5: 209. 1921) and repeated the synonymy as presented by Bentham (l.c.). Blakely (Key Eucalypts: 231–232. 1934) accepted what Maiden had decided but only listed E. largiflorens in synonymy rather than the full synonymy presented by Maiden (l.c. 1910). Black (in Trans. Roy. Soc. South Australia 60: 168. 1936) applied the newly established Cambridge Rules from 1935, and on advice from T.A. Sprague was the first to suggest that the protologue was inadequate and that Eucalyptus bicolor should be regarded as a nomen nudum. This has been the consensus view in Australia since 1936 (Cameron in Vict. Naturalist 63: 42. 1946; Chippendale, l.c.; Slee & al., l.c.; Australian Plant Census, accessed 8 Sep 2025). The name Eucalyptus largiflorens appears in many floras and popular books on eucalypts (Elliot & Jones, Encycl. Austral. Pl. 4: 127. 1986; Jessop & Toelken, Fl. S. Austral. 2: 926. 1986; Walsh & Entwisle, Fl. Victoria 3: 983. 1996; Harden, Fl. N.S.W. 2: 137. 2000; Stanley & Ross, Fl. S.E. Queensland 2: 188. 2002; Brooker & Kleinig, Field Guide Eucalypts, ed. 2, 3: 315, 2004, ed. 3, 1: 214. 2006; Moore, Guide Pl. Inland Austral.: 172. 2005; Cunningham & al., Pl. Western N.S.W.: 524. 2011) and it is listed as a dominant species or component of 8 Regional Ecosystems in Queensland [Queensland Herbarium (2024) Regional Ecosystem Description Database (REDD). Version 13.1 (May 2024), accessed 11 Jul 2025] and 9 Plant Community Types in New South Wales [Environment and Heritage, BioNet (2022) Plant Community Types (PCT) Master List. Version C2.0 (2022), accessed 5 Aug 2025]. The acceptance of Eucalyptus bicolor over E. largiflorens would cause unnecessary disruption to botanists and enthusiasts alike, and it would benefit no-one to re-introduce a name that has not been used for 90 years. Miguel Garcia, librarian at the National Herbarium of NSW, scanned the relevant pages within Thomas Mitchell's Journal to the interior of Subtropical Australia. Juliet Anderson, collections and digitisation assistant at the Cambridge University Herbarium, scanned the high-definition photo of the Thomas Mitchell specimen.