Daviesia arthropoda Mueller (1874: 225)

Crisp, Michael D., Cayzer, Lindy, Chandler, Gregory T. & Cook, Lyn G., 2017, A monograph of Daviesia (Mirbelieae, Faboideae, Fabaceae), Phytotaxa 300 (1), pp. 448-450 : 448-450

4. Daviesia arthropoda Mueller (1874: 225) , Crisp (1981: 149), Crisp (1995: 1211), Craigie (2015: 27). Type: ‘In monte Olgae; E. Giles.’ Holotype: MEL; isotype: PERTH

Divaricate, glabrous shrubs, 0.5–1 m high, glabrous, glaucescent. Root anatomy unknown. Branchlets divaricate, spinescent, terete, ribbed. Phyllodes scattered, divaricate or ascending, narrowly obovate with an acuminate pungent apex, basally cuneate, articulate at branchlet, (16–)20–40(–90) × (2.5–)3–5(–7) mm; venation apparent and midrib more prominent on adaxial side. Unit inflorescences 1 or 2 per axil, umbellate, (1)2–4-flowered; peduncle (1–) 4–8 mm long; barren basal bracts oblong, hooded, keeled, lacerated at the apex, ca. 0.5–1 mm long; subtending bracts oblong, lacerated at the apex, slightly keeled, ca. 1 mm long. Pedicel 3–8 mm long. Calyx 3–3.5 mm long including the 0.5–1.2 mm receptacle; lobes ± equal, straight, triangular; upper 2 lobes ca. 1 mm long; lower 3 lobes ca. 0.75 mm long. Corolla : standard sessile, broadly elliptic, ca. 4 × 3 mm, occasionally with small calli, yellow with red infusion towards the centre; wings elliptic, auriculate, ca. 4.5 × 1.5 mm including the ca. 1 mm

A MONOGRAPH OF DAVIESIA

Phytotaxa 300 (1) © 2017 Magnolia Press • 25 26 • Phytotaxa 300 (1) © 2017 Magnolia Press

CRISP ET AL.

claw, yellow infused with red; keel half transversely broadly obovate, acute, auriculate, saccate, ca. 4 × 2.5 mm including the ca. 1.5 mm claw, yellow. Stamens strongly dimorphic: inner whorl of 5 with longer, slender, terete filaments and shorter, round, versatile anthers with confluent thecae; outer whorl of 5 with shorter, broader, compressed filaments and longer, slender, basifixed, 2-celled anthers; filaments free, overlapping. Pod obliquely shallowly obtriangular with an acuminate apex, compressed, 7.5–8 × 5–6 mm; upper suture almost straight to slightly sigmoid; lower suture acute but broadly rounded. Seed not seen. ( Fig. 5 ).

Flowering period:— April to August. Fruiting period: April to August.

Distribution:— Widespread and scattered across the sandy deserts of central Australia, from the Little Sandy Desert (Western Australia), through south-western Northern Territory and north-western South Australia to east of Windorah, Queensland.

Habitat:— Grows on sand dunes with spinifex, e.g. Triodia basedowii E. Pritzel (1918: 356) , and Acacia spp.

Conservation status:— National: Not listed. WA: Priority 3, possibly threatened or near-threatened but not yet adequately surveyed. NT: Least concern. Qld: Not listed. This species is considered possibly threatened (WA) but occurs mostly in uninhabited sandy deserts and is not often collected for this reason alone. Most collections have come from the Alice Springs to Uluru region, which has exceptional road access compared with the rest of the range of D. arthropoda .

Selected specimens (15 examined):— WESTERN AUSTRALIA. Giles: Between Anne Range and Walter Jones Range, ca. 24°40’S, 128°50’E, A. S . George 12088, 22 July 1974 ( AD, CANB, MEL, PERTH) . NORTHERN TERRITORY. Central Australia South: Ca. 6.5 km N of Ayers Rock , 25°18’S, 131°03’E, J. R . Maconochie 1821, 24 August 1973 ( AD, CANB, K, MO, NT, TEXAS); ca. 6.5 km NNW of Ayers Rock [ Uluru ], 25°18’S, 131°03’E, P. K . Latz 2656, 13 August 1972 ( BRI, CANB, DNA, MEL, NSW, NT); Bloods Range , ca. 24°40’S, 129°35’E, J. R . Maconochie 1401, 10 April 1972 ( AD, CANB, DNA, MEL, NSW, NT, PERTH) . SOUTH AUSTRALIA. Nullarbor: Maralinga, 31°10’S, 131°35’E, F. L . Hill 803, 7 September 1956 ( BM) . QUEENSLAND. Gregory North: Retreat to Jundah, 25°00’S, 143°10’E, S. T . Blake 12071, 11 July 1936 ( BRI) .

Affinity:— Daviesia arthropoda closely resembles D. sejugata and D. ulicifolia . The phyllodes of D. sejugata resemble those of D. arthropoda , though D. sejugata has more elliptic phyllodes (except for specimens on the Yorke Peninsula, South Australia) that are markedly thicker, whereas those of D. ulicifolia are ovate to occasionally elliptic, but never obovate nor as long as D. arthropoda nor as thick as D. sejugata . The inflorescences of D. sejugata and some subspecies of D. ulicifolia (e.g. subsp. aridicola , though these are more racemose, subsp. incarnata and subsp. ulicifolia ) are umbellate, though the peduncle and pedicel are much shorter than those of D. arthropoda . The standard of D. sejugata (except for specimens on the Yorke Peninsula, see discussion under this species) and D. ulicifolia has a claw, whereas D. arthropoda has a sessile standard. The standard in D. arthropoda is much less broad than that of D. sejugata (which is 6.5–7.5 mm).

Figures

FIGURE 5. Daviesia arthropoda. A. Flowering branchlet. B. Inflorescence with floral parts except calyx removed. C. Pod. A, B from George 12088, C from Latz 2656. Drawn by B-J. Osborne.