Daviesia oxylobium Crisp (1995: 1218)

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

64. Daviesia oxylobium Crisp (1995: 1218) . Type [approximate locality data given because the species is rare]: Western Australia, Avon, near Quairading , 31°50’S, 117°20’E, M. D. Crisp 6612, 20 July1980. Holotype: CBG; isotypes: K, MEL, NSW, PERTH

Bushy, erect shrubs to 1 m high, glabrous, smooth, glaucous. Root anatomy with anomalous secondary thickening (cord type). Branchlets ascending, terete, densely and finely ribbed. Phyllodes crowded, erect, linear-clavate, terete, acuminate and pungent at the apex, articulate at the base, 20–70 mm long, 1–1.5(–2) mm diam., densely and finely ribbed. Unit inflorescences 1–3 per axil, racemose, 3–5-flowered; peduncle 1–1.5 mm long; rachis 1–4 mm long; barren basal bracts forming a tight involucre at the base of the peduncle, triangular, ca. 0.5–0.75 m long; subtending bracts oblong, spreading at the tips, ca. 1 mm long. Pedicels clavate, 1–3 mm long. Calyx 2.5–3 mm long including the ca. 1.5 mm receptacle; lobes subequal, triangular, ca. 0.5 mm long. Corolla : standard very broadly to depressed-ovate, emarginate, 4–5.5 × 5.5–6 mm including the ca. 1 mm claw, with a deep central groove, rich yellow towards margins, deep pinkish red towards centre; wings broadly spathulate, slightly unequal in size, rounded and incurved at the apex, auriculate, saccate, ca. 5 × 2 mm including the ca. 1.5 mm claw, pinkish red; keel half transversely broadly elliptic with an acute apex, auriculate, saccate, ca. 4–4.5 × 1.75 mm including the 1.5 mm claw, deep red. Stamens strongly dimorphic: inner whorl of 5 with longer, terete filaments and round, versatile anthers with confluent thecae; outer whorl of 5 with broad, flattened filaments and slender, basifixed, 2- celled anthers; filaments free. Pod obliquely shallowly obtriangular, tapered to an acicular beak, turgid towards the base, 14–18 × 8–10 mm, thick-walled. Seed plump, broadly ellipsoid, ca. 4 mm long, 3 mm broad, 2.75 mm thick, red-brown; aril scarcely lobed, ca. 1.75 mm long, orange. ( Fig. 64 ).

Flowering period:— July and August. Fruiting period: September and October.

Distribution:— Western Australia, central wheatbelt, within an area approximately bounded by Quairading, Corrigin, Bruce Rock and Yorkrakine. There is also a single old record from farther west, near Wooroloo.

Habitat:— Heath with sclerophyll shrubs (kwongan), occasionally under Eucalyptus wandoo woodland, on sandy and lateritic soils.

Conservation status:— National: Not listed. WA: Priority 4, adequately known and near-threatened or not threatened, requiring regular monitoring.

Selected specimens (12 examined):— Approximate locality data are given because the species is rare. WESTERN AUSTRALIA. Avon: Sources of the Swan River , 31°50’S, 117°20’E, A . Eaton s.n., 1889 ( MEL 81143 ); east of York , 31°50’S, 117°30’E, A . Eaton s.n., 1893 ( MEL 81138 ); near Bruce Rock , 31°60’S, 118°10’E, R . D. Royce 7882, 29 July 1963 ( PERTH); between York and Tammin , 31°50’S, 117°20’E, B. V. & M . Smith s.n., 7 October 1979 ( PERTH 5146712 ); N of Bruce Rock , 31°50’S, 118°10’E, C. E . & D.T. Woolcock D232, 11 August 1982 ( CBG) .

Affinity:— Superficially, D. oxylobium resembles D. teretifolia closely, mainly in the erect, clavate, pungent phyllodes; however, the phyllode striations are more sharply defined in D. oxylobium . Moreover, D. teretifolia is not close phylogenetically ( Fig. 1B ) and is easily distinguished by its conspicuously longer pedicels (8–15 mm long) and larger flowers (e.g. calyx ca. 5 mm long, standard 8–10 mm broad). Daviesia apiculata also has terete phyllodes and could be confused with D. oxylobium but differs in having apiculate, semi-pungent (not acicular) phyllodes, relatively narrower wings, united upper calyx-lobes, and a compressed pod that is acute rather than beaked.

A MONOGRAPH OF DAVIESIA

Phytotaxa 300 (1) © 2017 Magnolia Press • 149 150 • Phytotaxa 300 (1) © 2017 Magnolia Press

CRISP ET AL.

Despite a relatively distant phylogenetic relationship D. oxylobium is similar to D. daphnoides in the inflorescence, floral parts, fruits and seeds. However, the flat, narrowly elliptic phyllodes of D. daphnoides immediately distinguish it from D. oxylobium . Among the differences between these species in floral morphology is the truncate upper lip of the calyx in D. daphnoides versus the shallow deltoid upper lobes in D. oxylobium .

VII.a. D. benthamii Clade

Figures

FIGURE 1A. Phylogeny (part) of Daviesia estimated using maximum likelihood (PHYML) from concatenated sequences of ITS (nrDNA), and ndhF and trnL–trnF (cpDNA). The tree was rooted using the monotypic sister groups Viminaria and Erichsenia (not shown). The informal clade names are used for reference in the taxonomic treatment. Numbers on branches show non-bootstrap support. The tips are labelled with the taxon name and sample accession number.

FIGURE 64. Daviesia oxylobium. A. Flowering branchlet. B. Inflorescence. C. Pod. A, B from Crisp 6612 (type); C from Eaton s.n. (MEL 81143). Drawn by A.L. Prowse. Adapted from Crisp (1995) with permission from CSIRO Publishing.