Daviesia bursarioides Crisp (1995: 1178)

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

12. Daviesia bursarioides Crisp (1995: 1178) . Type [approximate locality data given because the species is rare]: Western Australia, Irwin, near Three Springs , M. D. Crisp 6480, 16 July 1980. Holotype: CBG; isotypes: K, PERTH

Straggling shrubs to 2 m high, glabrous. Root anatomy unknown. Branchlets regularly divaricate at 45°, terete, striate, spinescent, pruinose. Phyllodes scattered, spreading or ascending, compressed or flattened horizontally,

A MONOGRAPH OF DAVIESIA

Phytotaxa 300 (1) © 2017 Magnolia Press • 47 narrowly obovate, apiculate, tapered to the articulated base, 3–20 × 0.75–2.5 mm, with obscure midrib and veins, rather fleshy, glaucescent. Unit inflorescences 1 per axil, subumbelliform (apically umbelliform, basally racemiform), 3–8-flowered, very diffuse, viscid on rachis, pedicels and bracts; peduncle 18–35 mm long; rachis from almost nil to 14 mm long; subtending bracts spreading or appressed, linear, ca. 1.5 mm long. Pedicels gently thickened upwards, constricted just below apex, 3–5 mm long. Calyx ca. 4 mm long including the 1–1.5 mm stipe-like receptacle, slightly 5-ribbed when dry, viscid; lobes subequal, depressed-triangular, apiculate, ca. 0.5 mm long. Corolla : standard strongly reflexed, broad-, very broad- or depressed-ovate, emarginate, 7.5–10 × 9–10 mm including the ca. 1.5 mm claw, with 2 thickened calli at the base of the lamina, yellow towards margins, maroon on veins and towards centre; wings obovate, rounded and incurved at apex, strongly auriculate, saccate, 6.5–7 × 3–3.5 mm including the 1.5–2 mm claw, deep pink; keel half broadly obovate, acute, scarcely auriculate or auricles absent, saccate, 5.5–6.5 × 2–2.5 mm including the 1.5–2 mm claw, maroon. Stamens strongly dimorphic: inner whorl of 5 with compressed filaments and versatile, very broad-ovoid anthers with confluent thecae; outer whorl of 5 slightly longer, with compressed filaments and basifixed, broad-ellipsoid, 2-celled anthers; filaments free. Pod obliquely very broadly to shallowly obtriangular, acuminate, compressed, stipe-like at base, 10–14 × 6–9 mm, coriaceous; upper suture barely sigmoid; lower suture acute but very broadly rounded. Seed broadly ellipsoid, slightly flattened, 4.5–5.2 mm long, 3–3.8 mm broad, 2–2.5 mm thick, orange-brown with black mottling; aril thickly lobed, ca. 2 mm long, creamy-white. ( Fig. 14 ).

Flowering period:— June to September. Fruiting period: August to December.

Distribution:— Localised around the Three Springs area in Western Australia.

Habitat:— In sandy gravelly lateritic clay on low rises in an undulating landscape. Vegetation is mallee shrubland dominated e.g. by Eucalyptus gittinsii Brooker & Blaxell (1978: 228) , Allocasuarina campestris (Diels in Diels & E. Pritzel 1904: 126) Johnson (1982: 74) and Banksia Linnaeus f (1782: 15).

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

Selected specimens (14 examined):— Approximate locality data are given because the species is rare. WESTERN AUSTRALIA. Irwin: Three Springs area , 29°40’S, 115°40’E, C . Chapman 8, 28 August 1972 ( CBG, PERTH); ibid., C . Chapman (37) B76 , 10 August 1976 ( CBG, MEL); ibid., M . D. Crisp 6317, 2 October 1979 ( CBG); ibid., C . Chapman (72)77, 18 September 1977 ( CBG, K); between Coorow & Arrino, 29°30’S, 116°E, W. E . Blackall 2606, September 1932 ( PERTH) .

Affinity:— Daviesia bursarioides is a very distinctive plant, diagnosed by the regular, divaricate branching pattern in combination with the spinescent branchlet apex and the small, narrowly obovate phyllodes. Vegetatively it resembles a Bursaria ( Pittosporaceae ) and cannot be confused with any other species in the genus. The elongated, partly umbelliform, partly racemiform inflorescences, as well as details of the flowers and fruits, suggest a relationship to D. costata and D. longifolia , though these species have striate linear phyllodes several cm long. The molecular phylogeny indicates that D. bursarioides is closest to D. divaricata , D. localis and D. pleurophylla ( Fig. 1A ), with which it shares a divaricating growth habit, spinescent branchlet tips, umbelliform inflorescences, reduced phyllodes and—with D. localis only—viscid pedicels and calyces. However, it is readily distinguished from all these by its obovate phyllode shape and much longer inflorescence. Daviesia pedunculata is similar in the inflorescence (especially the length), viscid pedicels and pruinose branchlets; however, the latter has larger (7–37 × 2–16 mm), pungent leaves and non-divaricate, non-spinescent branchlets.

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 14. Daviesia bursarioides. A. Flowering branchlet. B. Inflorescence in bud. C. Pod. A, B from Crisp 6480 (holotype); C from Crisp 6317. Drawn by A.L. Prowse. Adapted from Crisp (1995) with permission from CSIRO Publishing.