Hibiscus krichauffianus F.Muell., Rep.

McLay, Todd G. B., Barker, Robyn M. & Albrecht, David E., 2023, Morphological and environmental variation within Hibiscus krichauffianus (Malvaceae), and the recognition of two new species, H. verecundus and H. calcareus, Australian Systematic Botany 36 (6), pp. 457-477 : 466-471

Hibiscus krichauffianus F.Muell., Rep. pl. Babbage’s

Exped. 7–8 (Oct. 1859)

Type citation: ‘ Lake Gregory , Darling River’ . Type : So. [South] Australia, s. dat., Mr Babbage 1, Com. R. Schomburgk 9/71 (lecto, here designated: K000659853 !, Supplementary Fig. S1, bottom right corner). Residual syntypes: Minindee Creek , River Darling [=Menindee Creek, Darling River], T. H.Goodwin s.n ( MEL 0068091 A!, excluding upper left packet and lower two fragments, Supplementary Fig. S2); possible syntypes: mixed collections from Herb. Mueller mounted on same sheet as the lectotype, Darling river, Near Spencer’s Gulf etc. ( K s.n., p.p.) [excluding the left-most specimen, as this is H. calcareus ; see notes below under Typification] .

Hibiscus krichauffianus F.Muell. var. krichauffianus [Autonym established by P. A.Fryxell, Proc. Linn. Soc. New South Wales 92(3): 263 (1968)].

Shrub or subshrub to 0.4–1 m tall, typically erect and ascending. Branchlets very densely covered with sessile to shortly stalked stellate hairs 0.3–0.8 mm in diameter, indumentum white, silvery-white, grey or yellowish-white. Stipules persistent or abscising with age, filiform, filiform–linear or filiform–subulate, 2.5–8 mm long, 0.16–0.4 mm wide. Mature leaves simple and unlobed, petiolate; petiole 5–25 mm long, moderately to very densely covered with sessile or shortly stalked stellate hairs; lamina mostly ovate to lanceolate or oblong, occasionally broadly ovate, flat to weakly concave or sometimes weakly folded or conduplicate, 10–55 mm long, 5–35 mm wide; base obtuse, truncate or very broadly cuneate; margins dentate to crenate; apex obtuse to broadly acute; adaxial surface whitish-silver to grey, becoming greyish-green with age, abaxial surface paler (except in young leaves); abaxial main and lateral veins raised and obvious; stellate hairs on adaxial surface dense to very dense (rarely moderate), 0.2–0.8 mm in diameter, sessile to shortly stalked, multiradiate with 7–20(–30) rays; stellate hairs on abaxial surface dense to very dense, 0.25–0.75 mm in diameter, sessile to shortly stalked, multiradiate with 10–25 rays. Flowers solitary in leaf axils, occasionally cleistogamous; combined peduncle and pedicel 5–26 mm long, usually elongating in fruit, abscission line not obvious, usually 1–2(–13) mm from base, indumentum as for young stems and petioles, broadening distally and sometimes becoming obviously flattened, occasionally recurving in fruit. Epicalyx lobes 5–8 (rarely 10), narrowly linear or subulate, 7–16 mm long, to ~ 1 mm wide, one-half to the same length as the calyx at anthesis, fused basally for 1–4 mm (fused part of epicalyx sometimes difficult to distinguish from the pedicel), straight in flower and becoming recurved (rarely incurved) in fruit, usually entire at the apex but rarely bifurcating, with moderate to dense stellate hairs abaxially on the lobes and usually very dense hairs on the fused portion. Calyx 9–18 mm long at anthesis, enlarging to 20 mm long in fruit; lobes narrowly triangular to triangular, 5–9 mm long at anthesis, enlarging to 12 mm long in fruit, abaxial indumentum of moderate to very dense stellate hairs, adaxial indumentum of appressed or ascending 1- or 2-armed hairs intermixed with stellate hairs particularly distally, obscurely 1-nerved under hairs. Petals 17–35 mm long, adnate to staminal column at base but otherwise free, pale pink or mauve (rarely white), lacking basal spot, glabrous adaxially, with sparse to moderate stellate hairs abaxially towards the margin and apex on one side, sometimes extending towards the petal base. Staminal column 10–18 mm long, apex irregularly 5-lobed, with the stamens usually distributed singly along the distal ~ 7 mm of the column but sometimes distributed along almost the full length of the column; staminal filaments 1–5 mm long; anthers yellow. Style 5-branched, with branches 1.75–4 mm long, exserted 2–9 mm beyond the apex of the staminal column. Stigmas capitate, 0.5–0.6 mm wide, distinctly hairy, hairs 0.25–0.6 mm long. Ovary 5-locular, with hairs 0.5–1 mm long. Cleistogamous flowers with a cap 3–4 mm long, with simple and stellate hairs on the apical ~1.5-mm segment, the hairs very dense. Capsule ovoid to globose, 5–12 mm long, usually beaked, beak 1–2 mm long, densely covered with simple shiny appressed hairs, the apical hairs erect, 0.5–1 mm long and extending beyond apex of capsule. Seeds reniform (rarely subangular reniform), 2–3 mm long, dark brown, with a sparse to moderate indumentum of simple, white, wispy spreading hairs 0.2–0.4 mm long; funicular remnants brown, membranous and wing-like, on either side of the himum. ( Fig. 2 a, 3 a, 4 a.)

Distribution and habitat

Hibiscus krichauffianus is widely distributed in arid Australia, predominantly occurring in southern NT, SA, south-western Qld and western NSW, with more restricted occurrences in WA near the NT border and in north-western Victoria ( Fig. 1, grey squares). The species occurs on deep sandy substrates (yellow, brown or red) sometimes overlying limestone on sand dunes, sandy rises or sand plains. Most occurrences are in open shrublands and hummock grasslands.

Associated overstorey species include Acacia species (e.g. A. aneura F.Muell. ex Benth. , A. ligulata A.Cunn. ex Benth. , A. brachystachya Benth. and A. melleodora Pedley ), Atalaya hemiglauca (F.Muell.) F.Muell. ex Benth. , Dodonaea viscosa

Jacq., Eucalyptus concinna Maiden & Blakely , Eucalyptus socialis F.Muell. ex Miq. and Grevillea stenobotrya F.Muell.

Associated shrubs and herbs include Abutilon otocarpum F.Muell. , Aluta maisonneuvei (F.Muell.) Rye & Trudgen , Aristida holathera Domin , Chrysocephalum eremaeum (Haegi) Anderb. , Crotalaria cunninghamii R.Br. , Crotalaria eremaea F.Muell. , Eremophila macdonnellii F.Muell. , Eremophila willsii F.Muell. , Gyrostemon ramulosus Desf. , Lechenaultia divaricata F.Muell. , Phyllanthus lacunellus Airy Shaw , Polycalymma stuartii F.Muell. & Sond. ex Sond. , Portulaca oleracea L., Salsola australis R.Br. , Senna artemisioides (Gaudich. ex DC.) Randell , Sida ammophila F.Muell. ex J.H.Willis , Solanum coactiliferum J.M.Black , Tribulus hystrix R.Br. , Triodia basedowii E.Pritz. and Zygochloa paradoxa (R.Br.) S.T.Blake.

Phenology

Buds, flowers or fruit were recorded in all months of the year and flowering likely occurred in response to rainfall.

Conservation status

Given the wide distribution and common occurrence of this species on sand substrates, the conservation status is of Least Concern in Australia (International Union for Conservation of Nature 2012). In Victoria, this species only occurs in Ned’s Corner in the far north-western part of the state and is therefore considered Critically Endangered in the state (Flora and Fauna Guarantee Act Threatened list issued October 2021, https://www.environment.vic.gov.au/conservingthreatened-species/threatened-list, accessed August 2023). The addition of Hibiscus calcareus and H. sp. Belele Station (D. W.Goodall 3417) to the WA flora will require reassessment of H. krichauffianus in that state, as the species may only occur on the WA – NT border.

Etymology

Named for Friedrich Eduard Heinrich Wulf Krichauff (1824– 1904), a South Australian parliamentarian and friend of Ferdinand Mueller ( O’Neill 1974). Although originally published as krichauffianus , in later references and on some specimen labels Mueller changed the spelling of the epithet to either ‘ krichauffi ’ or ‘ krichauffii ’ for unknown reasons (e.g. Mueller 1868).

Affinities

Hibiscus krichauffianus appears to be most closely allied to H. calcareus but is also similar to H. verecundus and H. sp. Belele (D. W.Goodall 3417). Features distinguishing these species from H. krichauffianus can be found in the ‘Affinities’ sections for the species, Table 1 and the key.

Populations of the highly variable species Hibiscus sturtii and H. leptocladus Benth. occur within the distributional

range of H. krichauffianus and could possibly be confused with this species. Both H. sturtii and H. leptocladus represent species complexes that are currently undergoing taxonomic revision. Members of the H. sturtii complex have epicalyx lobes that are distinctly fused basally for> 4 mm (or if rarely less then the epicalyx lobes are never narrowly linear) and seed hairs that are appressed (or if rarely non-appressed then hairs dense and not wispy), whereas in H. krichauffianus the epicalyx lobes are only fused for 1–4 mm, and the seed hairs are wispy and not appressed ( Fig. 3). Members of the H. leptocladus complex differ from H. krichauffianus in having petals with a dark basal spot, capsules never having a dense covering of appressed hairs throughout, seeds with denser hairs and leaves that are green rather than whitish-silver to greyish-green.

Notes

We observed examples of specimens with both cleistogamous and chasmogamous flowers, indicating that the two reproductive modes can overlap on the same plant or potentially occur simultaneously. Our finding of cleistogamy being present in H. krichauffianus sens. strict. but absent in H. verecundus and only present on one specimen of H. calcareus , suggests that there may be a connection between this reproductive mode and an arid environment ( Culley and Klooster 2007).

Selected specimens examined (176 specimens)

WESTERN AUSTRALIA. Rawlinson Range, beside Gun Barrel Highway, 30–80 km north-west of Giles, May 1980, J. M. Bechervaise & J . Kelso 149 ( PERTH) . NORTHERN TERRITORY. 20 km SW Adelaide t/o, Sth Stuart Highway, 1 Mar. 1994, D. E. Albrecht 5774 (DNA, MEL, NT); Mt Wedge Station , 19 Jan. 1972, C. Dunlop 2450 ( CANB, DNA, PERTH); 15 miles [~ 24 km] North of Andado Homestead , s. dat., J. R. Maconochie 487 ( NT); W side of Stuart Hwy, 34.0 km by road S of the intersection of the road from Alice Springs township to the Alice Springs Airport., 12 Mar. 2021, D. E. Albrecht 16356 ( CANB) . SOUTH AUSTRALIA. On N side of plant fence, ~ 30 m away Merrimelia Oil, 22 Nov. 2011, C. J. Brodie & P. J . Lang 3402 ( AD); Lake Littra , 16 Mar. 1997, R. Bates 46564 ( AD); 6.1 km W from Mt Hoare , 22 Sep. 2001, P. D.Canty BS23-38895 ( AD 121328 , DNA D0182575, NT D0182575 ); Officer Creek , 26 Apr. 1961, R. Bates 58204 ( AD); Dulkaninna Station , 5 Apr. 1997, H. Smyth 38 ( AD); Mount Gason , 11 Apr. 1997, D. E. Symon 15642 ( AD); ~ 9 km east from base camp. Base camp ~ 61 km east of Dalhousie Springs. Dalhousie Springs, ~ 115 km north of Oodnadatta , 11 Aug. 1963, T. R. N. Lothian 1779 ( AD); 7 km south of Roxby Downs township , Purple Downs Stations, 21 Feb. 1990, F. J. Badman 4149 ( AD); Wilgena, Carnding block, 13 Dec. 1962, leg. ign. s.n. ( AD 97629404 ); 1.9 km NE from Candradecka Dam, 11 Nov. 1996, R. Brandle & S. E . Ruff BS69- 29551 ( AD) . QUEENSLAND. 28.8 km south of Thylungra on Windorah – Quilpie Road, 12 Sep. 1990, M. E. Ballingall 2629 ( AD, BRI); ~ 58 km NW of Birdsville ~ 10 km S of Halffinish via road to Birdsville , Adria Downs Stn, 22 Feb. 1997, W. E. Edmunds AD179 ( BRI) . NEW SOUTH WALES. Eastern edge of Lake Victoria, ~ 50 km WNW from Wentworth, I. Sluiter s.n. ( CANB); Sturt National Park , 1 Oct. 1976, W. E. Mulham W915 ( NSW); 5.4 km WSW of Bottom Bore on the Fort Grey road, 8 May 1977, R. Chinnock 3545 ( AD, MEL); Wanaaring–Milparinka Road , 25 km E of Clifton Bore, 7 Nov. 1971, A. N. Rodd 1935 ( AD, BRI, NSW); Mt Jack cattle paddock, east of Whitecliffs , 9 Mar. 1979, J. W. Lawrie 1646 ( NSW) . VICTORIA. Freehold land of Rod Stoeckel in far NW corner of state ( N of Lindsay Point [Homestead]), 15 Mar. 2007, I. R. K. Sluiter 07/05 ( MEL) .

Typification

The name Hibiscus krichauffianus was first published by Mueller in 1859 in a ‘Report on the plants collected during Mr Babbage’s expedition into the north-western interior of South Australia in 1858’ but there were two reports with the same title ( Mueller 1859 a, 1859 b). The first ( Mueller 1859 a) was published in April in the Quarterly Journal & Transactions of the Pharmaceutical Society of Victoria. This article was a short, two-page summary of the Babbage expedition. Although several plant species are mentioned in the text, Hibiscus krichauffianus was not listed and this publication was not the original source of the name.

The second and more comprehensive report ( Mueller 1859 b) was tabled in the Victorian Parliament in October 1859 ( Churchill et al. 1978). This report began with the same two pages that appeared in Mueller (1859 a) and was followed by two pages that described the localities from which collections were obtained. An enumeration of the plants collected followed on page 6. A description of H. krichauffianus was provided on pages seven and eight of the report. Mueller’s (1859 b) description of H. krichauffianus was detailed, and the specimen examined clearly possessed flowers but no fruit and was only a small fragment:

Everywhere covered with an ashy velvet-like indument; upper leaves ovate or nearly orbicular, blunt, crenatetoothed; stipuls [sic.] almost setaceous; peduncles axillary and terminal, solitary, one flowered, as long as the petiole; involucre deeply divided into seven linear segments, which are of equal length with the nerveless calyx; petals three times longer than the calyx, blunt, oblong-cuneate, notched, slightly ciliate otherwise glabrous; styles and stamens glabrous; free parts of filaments arising singly from the columna [Latin: ‘column’], several times longer than the anthers.

Lake Gregory, Darling River.

The branches of the only small specimen which the collection contains are terete, slightly angular towards the summit. Leaves longer than the petiole, measuring about one inch. Calyx about five lines long [i.e. 11–12 mm long; see Stearn 1973, p. 113], with semilanceolate teeth. Petals probably pink, in the dried state pale, without spots, scarcely longer than one inch, blunt, not like in Hibiscus multifidus produced into an acute angle. Stamens half as long as the corolla [likely the staminal column], pale yellow. Pollen golden-yellow. Styles five, their free parts 1–1 ½ line long, yellow. Stigmas depressed, bearded [likely meaning hairy]. Capsules unknown.

It differs from Hibiscus Sturtii in longer peduncles, larger flowers, deeply cleft involucre, longer stipules, and a more ashy and velvety covering. [emphasis ours]

Prior to the publication of these two reports, Mueller discussed some of the plants from Babbage’s expedition in a letter to the director of Kew Gardens, William Hooker, dated 5 Feb. 1859 ( Home et al. 2022, letter 59.02.05, accessed July 2023), including a new species of Hibiscus and a new Eremophila speciesintended to be named after the South Australian governor of the time, Sir Richard Graves MacDonnell (1814–1881). Mueller also described the state of the collection (https://vmcp.rbg.vic.gov.au/text/letters/ 1850-9/1859/59-02-05-final/, accessed August 2023):

I have since commencing to write to you finished the examination of Mr Babbages plants… The collection contains 8 new sp of genera know [sic.], vize Hibiscus, Helichrysum, Trichinium, & Mr Dallachy has also returned and found like Mr Babbage a magnificent Eremophila … But the great mass of his collection has not yet arrived & may contain some novelty also… Mr Babbage has only 1 specimen of each plant glued up, so that I do not possess them myself, but I will print a full enumeration of them. I have broken a piece of[f] from his specimen of Babbagia. [emphasis ours].

In seeking candidate specimens for lectotypification we considered any material that could be linked to either Babbage or Herrgott 1 that could be reasonably matched to Mueller’s (1859 b) description, and included either of the localities mentioned in the protologue, i.e. Lake Gregory and Darling River . Although Mueller’s description in the protologue clearly indicated that only a single specimen was observed, this was at odds with the citation of two localities. Only Lake Gregory can relate to Babbage (or Herrgott) collections because the 1858 expedition did not approach the Darling River 2. Based on the protologue we identified several herbarium specimens as including possible syntypes of H. krichauffianus and evaluated these as being original material based on appearance and collection details (summarised in Table 2). These collections are housed in K, MEL and AD ; there are no Babbage Expedition specimens of H. krichauffianus in MEL .

All potential type specimens of H. krichauffianus at Kew are mounted on a single sheet (though with two accession numbers, K00659852 and K000659853 , and another one

1 Joseph Albert Franz David Herrgott (1823–1861), the botanist on the Babbage expedition, referred to by Mueller (1859 b, p. 4) as David Hergolt. The surname is also sometimes given as Hergott (see records in the Australasian Virtual Herbarium https://avh.chah.org.au/).

2 See list of locations in Mueller (1859 b, pp. 5–6).

required; see Supplementary Fig. S1). On the bottom right-hand side of the sheet is a specimen that is attributed to Babbage ( K 000659853). The material largely matches the protologue description well with an ashy indumentum, a deeply divided epicalyx and petals three times longer than the calyx, ~ 1 inch (~ 2.5 cm) long. However, there is a fruit on the specimen and no species name, locality information or date of collection. Notes on this specimen indicate that this was sent to Kew by Richard Schomburgk, director of the Adelaide Botanic Garden, in September 1871. Schomburgk sent several other specimens from Babbage’s expedition, including material of Eremophila macdonnellii 3 F. Muell. ( K 000961426) and Datura leichhardtii F.Muell. ex Benth. ( K 000759495) at the same time. Although specimen K 000659853 matches the overall description and is attributed to Babbage, the presence of the young fruit, the lack of locality information (aside from ‘So. [South] Australia’) and most significantly the lack of any scientific name on the label, means this is likely a duplicate of the specimen Mueller used in describing the species but was likely not observed.

The label on specimen K 000659852 (bottom left-hand side) was written by Mueller. However, this cannot be part of the type gathering, consisting of a single fruit with seeds, that the protologue explicitly stated were ‘unknown’ at the time of writing ( Mueller 1859 b, p. 8). This was also annotated as H. krichauffii , an orthographic variant introduced by Mueller after 1859, and was dated 1885, the year of collection and receipt by Kew. The unnumbered suite of specimens from Herb Mueller on the upper half of the same Kew sheet are from various localities and collectors, and discussed later.

The source of the ‘Darling River’ locality cited in the protologue requires clarification. Specimens of Hibiscus krichauffianus bearing this locality must have come from another of Mueller’s collectors since Babbage did not visit the locality. Although the collections from the Babbage expedition are the major subject of the report by Mueller (1859 b), material gathered by other collectors from arid areas and some northern Australian collections are also mentioned. The most likely source of Darling River collections was from the work of John Dallachy, a curator of the Melbourne Botanic Gardens, who, in 1858, ‘collected drought-resistant species along the River Murray near Wentworth and the Darling River as far north as Mount Murchison near Wilcannia’ ( Gross 1972). Dallachy was assisted in this task by the Rev. Thomas Hill Goodwin, a resident of the area, and the collections feature throughout Mueller’s report. Eremophila goodwinii F.Muell. ( Mueller 1859 b, p. 18) is named for Goodwin (also see the letter to Hooker, above, that mentions the collections made by Dallachy).

Specimen MEL 0068091 A (Supplementary Fig. S2) bears a white label attributing collection to Goodwin, with the locality ‘on sandhills near Minindee Creek, River Darling’, collection date February 1859, and an annotation by Mueller on a blue label as H. krichauffianus . Information on the white label matches the information on the envelope in the upper right packet, linking that material with the four uppermost sprigs on the sheet based on morphology. The packet contains two fruit and seeds and is written in Mueller’s hand. The packet and both labels are annotated with a ‘B’, indicating that Bentham saw this material. However, this material cannot have been used in producing the original description as fruit are included and the vegetative material is not a good overall match for the description (consisting of many fragments, a poor match for the Babbage specimen in Kew). Although the material was almost certainly not used in drawing up the description in the protologue, this was likely the source of the Darling River locality cited in the protologue and nonetheless a syntype.

Further adding to the complexity is that this sheet comprises two different entities based on our recircumscription of the species: Hibiscus krichauffianus sens. strict. and H. calcareus . The four uppermost mounted sprigs and fragments within the packet (comprising fruit, seeds and a leaf) fixed in the top right-hand corner of the sheet in Supplementary Fig. S2 match Hibiscus krichauffianus sens. strict. (morphotype A). Details on the white label notably match the information written on the packet mounted at the top right-hand side of the sheet containing material of morphotype A. The two lowermost mounted sprigs and fragments within the packet fixed in the top left-hand corner of the sheet in Supplementary Fig. S2 match H. calcareus (morphotype C), including the overall colour, leaf dentation, leaf folding and epicalyx characters. These specimens are also presumably from the Darling River where the two species overlap in distribution. In recircumscribing H. krichauffianus , we have excluded these specimens from our concept of H. krichauffianus sens. strict. and consider these specimens of H. calcareus .

Other MEL collections of Hibiscus krichauffianus from the Darling River were collected after 1860 and these were too late to be syntypes for the name (e.g. Beckler, Victorian Expedition ( MEL 0068092 A); H.Forde s.n. ( MEL 2223351 A) (likely Helena Forde (née Scott ), who collected for Mueller in the Darling River area in the late 1860s and 1870s; see Maroske and Vaughan 2014, p. 132) .

A specimen housed at the State Herbarium of South Australia in Adelaide (South Australia, s. dat., Anon. s.n. ( AD 97611531)), part of Schomburgk’s herbarium, has minimal information but may have come from Babbage as

3 Eremophila macdonnellii was lectotypified by Chinnock (2007, p. 406) on MEL 83174, a specimen from Lake Gregory that was attributed to Herrgott even though Herrgott’s name is not present and there is a blue label with the initial ‘B’, presumably indicating Babbage. The history surrounding the type specimens of E. macdonnellii likely mirrors that of H. krichauffianus but there is no material of the latter species at MEL bearing Herrgott’s name.

Schomburgk presented Babbage material to Kew in 1871. However, this is not a ‘small specimen’ as described in the protologue of the original material, the specimen does not match the Babbage specimen in K and the lack of any information means that other candidates could be the collector. We have discounted this specimen as a potential type .

On the Kew sheet that includes the specimens K 000659853 and K 000659852 are five additional sprigs that have no Kew catalogue number associated with them. They are all from Herb. Mueller and reference multiple locations (‘Darling River, near Spencer’s Gulf, etc.’). Bentham labelled this collection as H. krichauffii and the collections likely relate to the treatment in Flora australiensis ( Bentham 1863). In the treatment the Victorian Expedition (that departed from Melbourne in 1860 after publication of the protologue of H. krichauffianus ) was listed as the source of specimens from the Darling River and Cooper’s Creek, the Babbage Expedition of specimens from Lake Gregory and Major Peter Warburton (1813–1889) collected specimens from Spencer’s Gulf 4. However, the initial ‘B’ on the Goodwin collection ( MEL 0068091 A) indicates that Bentham also saw this collection for Flora australiensis ( Bentham 1863), therefore Goodwin could also have been cited for the Darling River locality. Bentham notably cited the Babbage Expedition as the source of material from Lake Gregory, therefore one of the fragments from Mueller’s herbarium was almost certainly original material. The Babbage specimen ( K 000659853) was sent to Kew in 1871 and could therefore not be the material Bentham referred to in Flora australiensis.

As one or more of these five unnumbered specimens possibly relate to the original Babbage material ( K000659853 ) or the Goodwin material ( MEL 0068091 A), these could be considered original material or syntypes. The leftmost fragment on the sheet at K appears to be different from the other specimens as this is a paler grey with smaller, more dentate leaves and appears to be similar to morphotype C , the newly described H. calcareus , as mentioned above. This fragment matches a MEL specimen ( MEL 2223362 ) collected by Warburton ‘ towards Spencers Gulf’ . This specimen lacks a date but is not a syntype of H. krichauffianus as no Warburton collections were mentioned in the protologue (although Warburton had been in the Gawler Range area in 1857 and replaced Babbage on the expedition to Lake Torrens in 1858; Orchard 1999, p. 75). Moving left to right, the second fragment of the five can be ruled out as original material as this is small and lacks any reproductive material. The fifth fragment can also be ruled out as this includes a fruit. However, fragments three and four could be original material related to the Babbage collection ( K000659853 ) .

4 Distribution statement ( Bentham 1863, p. 216): ‘ N. S. Wales. Darling river, Victorian Expedition. S. Australia. Lake Gregory, Babbage’s Expedition; Cooper’s Creek, Victorian Expedition; towards Spencer’s Gulf, Warburton.’

To typify H. krichauffianus , a type must be selected from K 000659853, MEL 0068091 A or the unlabelled Kew specimens from Mueller’s herbarium, though each has drawbacks. K 000659853 is attributed to Babbage but includes a fruit and therefore does not perfectly match the protologue. Specimens mounted as MEL 0068091 A are likely part of the type gathering, representing the Darling River locality in the protologue but do not match the protologue description well. The material from Mueller’s herbarium mounted on the same sheet as K 000659853 potentially includes material from both the Babbage and Goodwin collections, though we cannot be certain as to whether specimens three or four on that sheet represent the original material. We therefore decided to lectotypify the name Hibiscus krichauffianus on K 000659853, as this is likely a duplicate of the material Mueller used to prepare the protologue. MEL 0068091 A therefore becomes a residual syntype and the unlabelled Kew specimens (the third and fourth fragments) are possible residual syntypes.

Excluded taxon

Hibiscus krichauffianus var. chippendalei Fryxell, Proc. Linn. Soc. New South Wales 92(3): 263 (1968).

= Hibiscus leptocladus Benth. , in part (taxonomic synonym, includes holotype).

= Melhania oblongifolia F.Muell. , in part (misapplication with respect to the Nicholls’ collections).

Specimens cited by Fryxell (1968, p. 263): ‘ Northern Territory: Rare in grey sandy soil in woodland, 52.2 miles [~ 84 km] N. W. of Newcastle Waters , G. Chippendale s.n., 18 April 1959, ( NT 5826 , Holotype) : ¼ mile [~ 400 m] N. of Alice Springs trucking yards, A. Nicholls 519 ( NT) 524 ( NT) 525 ( NT, TAES), 11 May 1967 ’.

Hibiscus krichauffianus var. chippendalei was described by Fryxell (1968, p. 263) based on material collected from the Northern Territory and is currently cited as a name of uncertain application in the Australian Plant Census ( APC, https://biodiversity.org.au/nsl/services/rest/treeElement/ 51731610/51229594; accessed August 2023). However, this has previously been cited as a synonym of Melhania oblongifolia ( Jacobs and Pickard 1981) and Hibiscus leptocladus ( Mitchell 1981) .

Fryxell designated a specimen from NW of Newcastle Waters ( G.Chippendale s.n., NT 5826; DNA A 0005826) as the holotype of the new variety name and cited four additional specimens collected from near Alice Springs (viz. Nicholls 519 ( NT), 524 ( NT) and 525 ( NT, TAES)). Andrew Mitchell ( NT) examined the holotype on 9 April 1975 and later listed H. krichauffianus var. chippendalei in synonymy under H. leptocladus in Mitchell (1979) and in the Flora of Central Australia treatment of Hibiscus ( Mitchell 1981) . We have examined the holotype of H. krichauffianus var. chippendalei and agree with Mitchell’s assessment that this is a specimen of H. leptocladus . 5

The other specimens of Hibiscus krichauffianus var. chippendalei cited by Fryxell (Nicholls 519 ( NT), 524 ( NT) and 525 ( NT, TAES)) were redetermined by Ian Cowie (DNA) as Melhania oblongifolia while preparing the Melhania treatment for the Flora of the Darwin Region (Ian Cowie, pers. comm., November 2018). Jacobs and Pickard (1981) also listed H. krichauffianus var. chippendalei as a synonym of Melhania oblongifolia in the census of the plants of New South Wales. Fryxell’s concept is therefore a partial misapplication to Melhania oblongifolia and should therefore be listed as such under the synonymy of that taxon.