(2758) Eremophila R. Br., Prodr.: 518. 27 Mar 1810 [Myopor./Scrophular.], nom. cons. prop.

Typus: E. oppositifolia R. Br.

(=) Bontia L., Sp. Pl.: 638. 1 Mai 1753, nom. rej. prop.

Typus: B. daphnoides L.

(=) Myoporum Sol. ex G. Forst., Fl. Ins. Austr.: 44. Oct–Nov 1786, nom. rej. prop.

Typus (fide Webster in Pacific Sci. 5: 59. 1951): M. laetum G. Forst.

(=) Andreusia Vent., Jard. Malmaison: ad t. 108. Jul 1805, nom. rej. prop.

Typus: A. glabra (Andrews) Vent. (Pogonia glabra Andrews).

Eremophila R. Br. (Prodr.: 518. 1810), with ca. 230 named and accepted species (plus 59 segregate subspecies) all endemic to Australia, is one of seven genera commonly recognised (e.g., Chinnock, Eremophila Allied Gen.: Monogr. Myoporaceae. 2007) in the tribe Myoporeae of the family Scrophulariaceae (as circumscribed by Oxelman & al. in Taxon 54: 411–425. 2005). When published, Eremophila included two species, E. oppositifolia and E. alternifolia; the former was designated as type by Smith (in Contr. Queensland Herb. 19: 4. 1975). Following the treatment of Chinnock (l.c. 2007), the other genera are: Bontia L. (Sp. Pl.: 638. 1753), with one species from the Caribbean‐Bahamas; Calamphoreus Chinnock (l.c. 2007), with one species from Western Australia; Diocirea Chinnock (l.c. 2007), with four species from Western Australia; Glycocystis Chinnock (l.c. 2007), with one species from Western Australia; Myoporum Sol. ex G. Forst. (Fl. Ins. Austr.: 44. 1786), with 30 species in Australasia, the Pacific and Indian Ocean; Pentacoelium Siebold & Zucc. (in Abh. Math.‐Phys. Cl. Königl. Bayer. Akad. Wiss. 4(3): 151. 1846), with one species from southern Japan and southern China, including Taiwan and Hong Kong.

Phylogenetic analyses of nuclear and chloroplast DNA sequences (Fowler & al. in Pl. Syst. Evol. 306: 52. 2020; Fowler & al. in Taxon, submitted) indicate that Eremophila, as usually circumscribed, is paraphyletic, with all other genera of Myoporeae nested in it. Revision of generic limits in this group is clearly warranted, and a number of approaches could be taken in order to establish a generic classification that recognises only monophyletic groups. Because some relationships remain poorly supported or resolved, and because clear morphological apomorphies have not been recognised for some molecular clades, the recognition of multiple genera, in the absence of further data, is problematic. The simplest taxonomic solution is to place all species in the tribe in a single genus. This could cause substantial taxonomic change, and we here outline a proposal, under provisions of Art. 14 of the ICN (Turland & al. in Regnum Veg. 159. 2018), to minimise the impact of such change.

If all members of Myoporeae are placed in a single genus, adherence to the principle of priority dictates that the name of that genus should be Bontia. This would cause significant nomenclatural disruption. Linneaus described the genus Bontia based on B. daphnoides L. (l.c. 1753), endemic to the Caribbean and adjacent areas. He subsequently (Sp. Pl., ed. 2.: 891. 1763) described a second species, but that is now placed in the genus Avicennia (family Acanthaceae), and Bontia has historically been considered monotypic by most relevant works on Myoporeae/Myoporaceae (e.g., Candolle, Prodr. 11: 716. 1847; Wettstein in Engler & Prantl, Nat. Pflanzenfam. 4(3b): 359. 1895; Carlquist & Hoekman in Aliso 11: 317–334. 1986; Chinnock, l.c. 2007). The notable exception is that Kuntze (Revis. Gen. Pl. 2: 500–501. 1891) expanded the circumscription of Bontia to include the 61 species of Australian eremophilas known at the time. He subsequently (Post & Kuntze, Lex. Gen. Phan.: 73–74. 1903) proposed a sectional classification of Bontia that also included Myoporum, but did not make any associated combinations at species rank. Such broad circumscriptions of Bontia have not been followed by other authors. Adopting such a classification, and the rules of priority, would displace widely used names and require at least 276 new combinations at species and subspecies level in the tribe Myoporeae.

If Myoporeae is treated as monogeneric, nomenclatural stability would be maximised if the name Eremophila could be used for the sole genus. This would minimise the number of new combinations needed (ca. 39 at species and infraspecific ranks), and it would retain a name that is widely known and used. Although the limits of Eremophila have varied over time, as summarised by Smith (l.c.) and Chinnock (l.c. 2007), the generic name has been used, in some circumscription, in all relevant works and floras, with the notable exception of the works of Kuntze (l.c.) and Post & Kuntze (l.c.), which adopted a broader circumscription of Bontia, and of Baillon (Hist. Pl. 9: 421. 1888) and Wettstein (l.c.), who mistakenly thought that the name Pholidia R. Br. (Prodr.: 517. 1810) had priority over Eremophila because of pagination in the protologue. Mueller (Rep. Pl. Babbage's Exped.: 16–18. 1859) proposed a broad circumscription of Eremophila (including Pholidia; Art. 11.5) that has been widely adopted by Australian checklists, printed floras (e.g., Chinnock in Jessop, Fl. Centr. Australia: 338–348. 1981; Chinnock in Jessop & Toelken, Fl. S. Australia 3: 1325–1348. 1986; Stanley in Stanley & Ross, Fl. S.E. Queensland 2: 463–467. 1986; Chinnock in Harden, Fl. New S. Wales 3: 540–550. 1992; Jeanes in Walsh & Entwisle, Fl. Victoria 4: 528–539. 1999), online floras and databases (e.g., FloraNT: Northern Territory Flora online [http://eflora.nt.gov.au/]; PlantNet [http://plantnet.rbgsyd.nsw.gov.au]; FloraBase [https://florabase.dpaw.wa.gov.au], VICFLORA [https://vicflora.rbg.vic.gov.au]; Electronic Flora of South Australia [http://www.flora.sa.gov.au]; Australian Plant Census [https://www.anbg.gov.au/chah/apc/]), and guide books (Grieve & Blackall, How to Know W. Austral. Wildfl. 4: 621–654. 1975; Costermans, Native Trees Shrubs S.E. Australia: 272–276. 1981; Cunningham & al., Pl. W. New S. Wales: 606–616. 1992; Brown & Buirchell, Field Guide Eremophilas W. Australia. 2011), with some most recent works differing only by recognition of the small segregate genera Calamphoreus, Diocirea and Glycocystis proposed by Chinnock (l.c. 2007). Eremophila plants are very commonly grown in gardens, thus the name Eremophila is very widely used in the horticultural industry, especially in Australia, and since 1972 there has been an active “Eremophila Study Group” (http://www.anpsa.org.au/eremophilaSG/index.html), which is affiliated with the Australian Plants Society. The name Eremophila is also widely used in studies of plant chemistry (e.g., Jefferies & al. in Austral. J. Chem. 15: 532–537. 1962; Croft & al. in Tetrahedron 33: 1475–1480. 1977; Ghisalberti & al. in Austral. J. Chem. 37: 635–647. 1984; Forster & al. in Tetrahedron 42: 215–221. 1986; Beattie & al. in Phytochemistry 72: 400–408. 2011), including assays of bioactivity and Aboriginal medicinal uses (e.g., Richmond in J. Adelaide Bot. Gard. 23: 101–107. 1993; Pennacchio & al. in J. Ethnopharmacol. 53: 21–27. 1996; Ndi & al. in J. Basic Microbiol. 47: 158–164. 2007; Smith & al. in J. Ethnopharmacol. 112: 386–393. 2007; Sadgrove & al. in J. Ethnopharmacol. 154: 758–766. 2014; Youssef & al. in J. Pharm. Pharmacol. 69: 733–742. 2017), associations with insect hosts (e.g., Richmond & al. in Austral. J. Entomol. 34: 29–30. 1995; Exley in Rec. W. Austral. Mus. 18: 419–437. 1998; Cassis & Symonds in Acta Entomol. Mus. Nat. Pragae 48: 433–484. 2008; Cassis & Symonds in Zootaxa 2818: 1–63. 2011; Symonds & Cassis in Austral. J. Entomol. 52: 53–66. 2013; Schuh & Schwartz in Bull. Amer. Mus. Nat. Hist. 401: 1–279. 2016), and studies of plant ecology (e.g., Burrows in Austral. J. Bot. 20: 317–329. 1972; Gardiner in Rangeland J. 8: 18–27. 1986; Watson & al. in J. Ecol. 85: 833–846. 1997; Cochrane & al. in J. Roy. Soc. Western Australia 85: 31–35. 2002). A Google Scholar search (scholar.google.com, accessed 15 Jun 2020) for “Eremophila” + “plant” returned 8910 records (in comparison to a search for “Bontia” + “plant” that returned only 417 records).

Although minimising taxonomic change, use of the name Eremophila for all members of a monogeneric Myoporeae would have the disadvantage of displacing the name Myoporum. The genus Myoporum, as circumscribed by Chinnock (l.c. 2007) and most current works, includes substantially fewer species than Eremophila, but its name is widely used because of its extensive geographic range, including the Mascarene Islands, Australia, New Guinea, Timor, Bonin Islands, Marianas Islands, New Zealand, New Caledonia, Vanuatu, Cook Islands, Society Islands, Tubuai Islands and Hawaii. A Google Scholar search (scholar.google.com, accessed 15 Jun 2020) for “Myoporum” + “plant” returned 5070 records. Loss of this well established and widely used name would clearly be disruptive. Such a loss would also be the outcome if the rules of priority were strictly enforced, and the name Bontia was used for a monogeneric Myoporeae. In seeking to apply the ICN provisions for conservation of names, we are here proposing that Eremophila should be conserved over Myoporum, thus attempting to minimise the total number of taxonomic changes, rather than the geographic impact of those changes. If we were, instead, to propose use of the name Myoporum for a monogeneric Myoporeae (by conserving Myoporum over Bontia) it would require at least 294 new combinations at species and infraspecific ranks, and also displace the equally well‐established name Eremophila.

In order to mimimise taxonomic disruption and to apply the name Eremophila to a monogeneric Myoporeae, that generic name will need to be conserved not only against Bontia and Myoporum, but also against Andreusia Vent. (l.c.). The generic name Andreusia was applied by Ventenat (l.c.) to two Australian species, and was used by Steudel (Nomencl. Bot., ed. 2. 1840) for two additional species, but the name has otherwise not been widely used, usually being considered synonymous with Myoporum (e.g., Bentham, Fl. Austral. 5: 8. 1870; Mueller, Syst. Census Austral. Pl.: 104. 1882; Domin in Biblioth. Bot. 22(89): 1164. 1929; Chinnock, l.c. 2007; Australian Plant Census, https://biodiversity.org.au/nsl/services/apc). In line with the spirit of Art. 14 of the ICN, it would be illogical to conserve the name Eremophila against Bontia and Myoporum without also conserving it against the little‐used name Andreusia.

In summary, for the reasons outlined above, we propose that the name Eremophila be conserved against Bontia, Myoporum and Andreusia under the provisions of Art. 14 of the ICN. This would substantially reduce taxonomic upheaval when members of tribe Myoporeae are combined in a single genus.