Erythrophleum arenarium R.L.Barrett & M.D.Barrett, 2023

Barrett, Russell L. & Barrett, Matthew D., 2023, Taxonomic revision of Australian Erythrophleum (Fabaceae: Caesalpinioideae) including description of two new species, Australian Systematic Botany 36 (5), pp. 401-426 : 412

Erythrophleum arenarium R.L.Barrett & M.D.Barrett , sp. nov.

Type: Frome Rocks Road , 18 miles [~ 29 km] south-east of Manguel Creek Station Homestead , SW Kimberley, Western Australia, 21 October 1984, D.Fell 297 (holo: PERTH 02211947 ; iso: BRI AQ444796 ) .

Tree up to 6(–8) m tall, sometimes a shrub, few-branched with a compact crown, resprouting after fire; bark dark grey to blackish, roughly tessellated; branchlets usually glabrous, sometimes a little corky, sometimes slightly glaucous at the nodes. Leaves with petiole 42–55 mm long; rachis 14–40 mm long; pinnae usually 2(3) pairs, sometimes 1 or 2 pinna aborted so appearing alternate; secondary rachises 40–110 mm long; leaflets alternate, mostly 2–5(–7) per pinna, orbicular to somewhat deltoid, mostly 29–74 mm long, 27–83 mm wide, slightly larger on resprout growth (up to 87 mm long, up to 97 mm wide), obtuse to cordate, ±symmetric or slightly asymmetric, rounded, obtuse or emarginate apically, glabrous or slightly glaucous; petiolules 4–9(–11) mm long; venation conspicuous. Racemes mostly 80–140 mm long; axis 1.0– 2.1 mm thick below the flowers, glabrous. Flowers 72–88; distinctly pedicellate, pedicels 3.0– 5.5 mm long at anthesis; cream to greenish-yellow. Floral bracts 1.5–2.5 mm long, margins fimbriate, lamina glabrous. Calyx 3.6–5.0 mm long; lobes shorter than the tube, 1.1–2.1 mm long, pubescent only on margins. Petals 4.2–6.4 mm long, with pubescent margins and scattered hairs on the adaxial surface. Stamens alternately long and short, filaments 4.6–9.7 mm long, glabrous. Anthers 1.0– 1.3 mm long. Ovary densely pubescent, 3.6–5.3 mm long. Style 1.0– 2.2 mm long. Pod often slightly curved, dehiscing along both sutures, (1–)3–6-seeded, (85–) 145–175 mm long, 30–38 mm wide, apex acute to apiculate; dark reddish-brown, glabrous; stipe of pod often asymmetric, 11–33 mm long. Seeds brown, suborbicular, 12–14 mm long, 10–13 mm wide, 4.0–5.0 mm thick; aril 3–6 mm long. ( Fig. 2 )

Illustrations

D. E. Symon in J. P. Jessop (Ed.), Fl. Centr. Australia 104, fig. 127 (1981); K. F. Kenneally et al., Broome & Beyond. Pl. & People Dampier Peninsula 76, [lower pl. only] (1996); B. Kane, Broome’s Natural Environment (2023); http://wkfl. asn.au/nature/ironwood.html (accessed 9 August 2023), (all as E. chlorostachys ).

Distribution

Endemic in northern Australia, from the northern edge of the Pilbara, north to the Dampier District in the southern Kimberley and east through most of the Great Sandy Desert.

Habitat

Usually found in open pindan woodland or savanna on sand, often on old, subdued sand dunes.

Phenology

Flowering recorded for August–November and fruiting recorded for April, May, August, October and November.

Etymology

The epithet is derived from the Latin arenarius (pertaining to sand), in reference to the specific habitat of this species on sands associated with the Great Sandy Desert (see McKenzie et al. 1983).

Notes

The following combination of characters is diagnostic: tree up to 6(–8) m tall, few-branched with a compact crown, branchlets usually glabrous, sometimes glaucous. Leaves with pinnae usually in 2(3) pairs; leaflets mostly 2–5(–7) per pinna, orbicular to somewhat deltoid, not or slightly asymmetric; glabrous or slightly glaucous; petiolules 4–9(–11) mm long; raceme axis glabrous. Calyx 3.6–5.0 mm long; lobes 1.1–2.1 mm long, pubescent only on margins; pedicels 3.0– 5.5 mm long at anthesis; stipe of pod 11–33 mm long.

Ross (1998) noted that plants from the south-western Kimberley differed from the majority of the species’ range in their almost glabrous, pedicellate flowers that are also larger. Field observations have found these characteristics to be consistent, with plants readily identifiable as either E. arenarium or E. pubescens in a narrow zone of overlapping distribution in adjacent habitats between Willare Bridge and Blina, in Western Australia.

Known as camel poison. The common name of desert ironwood is suggested here as a more definitive name. First Nations names include joonggoomarr (Bardi), jun’ju, and bilamana (Yawuru) ( Kenneally et al. 1996).

Although reasonably widespread and not currently threatened, it is noted that some populations may be affected by mining for mineral sands on the Dampier Peninsula (https:// www.epa.wa.gov.au/1080-thunderbird-mineral-sands-project).

Representative specimens

WESTERN AUSTRALIA. 1 km NW of Dampier Downs Station northern gate, 1 Nov. 2014, R. L . Barrett & M . Gresser RLB 9080 ( CANB, DNA, NSW, PERTH); 23.3 km along pipeline track , ESE of Shay Gap , and NE of Marble Bar , 23 Apr. 2006, A. R . Bean 25079 ( BRI); Great Sandy Desert, 25 Apr. 1964, J. S . Beard 3249 ( PERTH); Anna Plains Road, 3 km from Great Northern Highway , 28 Sep. 2004, G. Byrne 1271 ( PERTH) ; between De Grey River and La Grange Bay, Carey s.n. ( MEL); near Racecourse, Broome , 31 Aug. 1991, B. J . Carter 484 (DNA, n.v., PERTH) ; 55 km SW of Derby , 12 Oct. 1985, H. Demarz 10906 ( PERTH) ; 25 km E of Port Hedland Road on Dampier Downs Road , 26 June 1984, S. J . Forbes 2465 ( HO n.v., MEL, PERTH); Millijiddee Homestead, St George Ranges, 5 May 1960, C. A . Gardner 12389 ( PERTH); McLarty Hills, Great Sandy Desert, 5 Aug. 1977, A. S . George 14639 ( PERTH) ; 94 km ESE of Telegraph Line, Anketell Ridge Road, Great Sandy Desert , 13 Aug. 1977, A. S . George 14819 ( PERTH); [near] Beagle Bay , 1879, A. Forrest & Carey ( MEL) ; 58 km SSW of No. 1 McHugh Bore on Dampier Downs Station , 26 Sep. 1980 , S. D.Hopper 1733 ( PERTH); near Roebuck Bay , Nov. 1967 , F. Lullfitz s.n. ( PERTH); Dampier’s Land near Broome , July 1911 , E. M. Mjöberg s.n. ( NSW); ~ 32 km E of Yeeda Homestead on the Great Northern Highway , 27 May 1967 , E. A. Shaw 810 ( AD); 12 km N of Pardoo Roadhouse on North West Coastal Highway , 23 Oct. 2015 , L. S. J. Sweedman 8997 ( PERTH) .

Figures

Fig. 2. Erythrophleum arenarium: (a) habitat and habit; (b) bark; (c) fruiting branchlet; (d) slightly glaucous leaf; (e) seedling; (f) portion of inflorescence; (g) inside view of legume with attached seeds; (h) young sapling with main stems killed by fire and multiple stems resprouting. Vouchers: north of Pardoo Roadhouse, WA, not vouchered (a, b, d); north of Dampier Downs Station, WA, R.L.Barrett & M.Gresser RLB 9080, PERTH (c, e, g, h); Anna Plains, WA, G.Byrne 1271, PERTH (f). Images by R. L. Barrett (a–e, g, h), and G. Byrne (f).