Daviesia euphorbioides Bentham (1864: 88)

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

130. Daviesia euphorbioides Bentham (1864: 88) , (Crisp 1995: 1193). Type : ‘W. Australia, Drummond, 3rd Coll. n. 76.’ Lectotype (Crisp 1995: 1193): K (ex Herb. Hooker); isolectotype: BM, G, K (ex Herb. Bentham), K (ex LINN), MEL, P (2 sheets), W

Open, erect to sprawling, cactus-like subshrubs, to 0.8 m high, glabrous, glaucous to pruinose. Root anatomy unknown. Branchlets mostly erect, terete, thick (6–10 mm diam.), appearing fleshy but filled with pith, smooth when fresh and longitudinally ribbed or wrinkled when dry. Phyllodes scattered and inconspicuous, acscending, divaricate or recurved, reduced to small spines tapering to an acicular pungent apex, 0.5–2.5(–5) mm long, 1–1.5 mm broad at the inarticulate base. Juvenile phyllodes leaf-like, elliptic, apically rounded with a small mucro, constricted to a petiole-like base, continuous with the branchlet, 18–20 × 7–11 mm; outer margins thickened, midvein apparent, strongly wrinkled when dry. Unit inflorescences 1 per axil, very condensed and crowded racemes, 3–6-flowered; peduncle 0.5–1.5 mm long; rachis <0.5 mm long; barren basal bracts numerous, clustered in an involucre at the base of the peduncle, to 0.75 mm long, broader than subtending bracts; subtending bracts ascending, oblong, tips fimbriate, to 1 mm long. Pedicel 1–1.5 mm long. Calyx 3–4 mm long including the 1–1.5 mm receptacle; upper 2 lobes united into a broad, truncate lip, usually <0.5 mm long; lower 3 lobes triangular, ca. 0.5 mm long; lobes slightly flared towards the apex. Corolla : standard very broadly obovate, emarginate, 7.5–9 × 6–8.5 mm including the 1–2 mm claw, with 2 thickened calli at the base of the lamina, bright yellow with a dark red-brown centre; wings obovate with a rounded, slightly incurved apex, auriculate, 6.5–7.5 × 2–3 mm including the 1.5–2 mm claw, maroon; keel half very broadly ovate, acute and slightly rounded apex, auriculate, saccate, 6.5– 9 × 2–2.5 mm including the 3.5–5 mm claw, maroon. Stamens slightly dimorphic: inner whorl of 5 with longer, slender, terete filaments and shorter, rounder, versatile anthers; outer whorl of 5 with shorter, broader, compressed filaments and longer, oblong, basifixed anthers; filaments cohering towards the base; anthers all 2-celled. Pods obliquely very broadly to shallowly obtriangular, wedge-shaped, acute, somewhat turgid, 13–16 × 10–12 mm; upper suture upwardly curved; lower suture acute to 90°. Seed not seen. ( Fig. 131 ).

Common name:— Wongan Cactus.

Flowering period:— July to September. Fruiting period: September to January.

Distribution:— Western Australia, north-central wheatbelt, recorded from an area delimited by Wongan Hills, Dowerin and Moonijin.

Habitat:— Grows in rocky loam to deep sand in disturbed areas around gravel pits, and along roadsides and railway lines, in heath with Allocasuarina campestris and Callitris . This species is short-lived and is possibly an obligate re-seeder following fire.

Conservation status:— National: Endangered. WA: Critically Endangered, Declared Rare Flora.

Selected specimens (18 examined):— Approximate locality data given because the species is rare. WESTERN AUSTRALIA, Avon: Wongan Hills area , 30°50’S, 116°40’E, M . D. Crisp 6320, et al., 2 October 1979 ( CBG); ibid., M . D. Crisp 6520, 17 July 1980 ( CBG); ibid., C. A . Gardner 12457, 7 August 1960 ( PERTH) ;

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ibid., C. A . Gardner s.n., 5 September 1924, juvenile material present ( PERTH 05212286 ) ; ibid., 32°52’S, 116°42’E, J . Taylor 2172 & P . Ollerenshaw, 23 September 1983 ( CBG, MEL); Moonijin area , 31°S, 117°10’E, M . D. Crisp 6684, 23 July 1980 ( CBG, K, PERTH) .

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Affinity:— The unique cactus-like habit makes this species unlikely to be confused with any other in Daviesia .

In particular, all other species have much thinner branchlets that are woody and not filled with parenchyma.

Figures

FIGURE 131. Daviesia euphorbioides. A. Flowering branchlet. B. Inflorescence with flowers represented by calyces only. C. Pod. A, B from Crisp 6520; C from Crisp 6320. Drawn by B-J. Osborne.