Daviesia purpurascens Crisp (1980a: 274)

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

71. Daviesia purpurascens Crisp (1980a: 274) , Crisp (1981: 150), Crisp (1995: 1226). Type: Western Australia, 6.3 km N of Bendering on Narembeen road, 32°20’S, 118°19’E, M.I.H. Brooker 6329, 12 August 1979, fl., spirit material. Holotype: CBG; isotypes: AD, CANB, K, NSW, PERTH

Glabrous shrubs, with many stems, to ca. 1 m high, glabrous, grey-green to purplish-glaucescent. Root anatomy normal (unistelar). Branchlets numerous, ascending or erect, rigid, flexuose. Phyllodes scattered, divaricate to ascending, terete, gently tapered, pungent, inarticulate at base, 5–50 mm long, 0.7–1.5 mm diam., rigid, smooth when fresh, wrinkled-striate when dry. Unit inflorescences 1–3 per axil, racemose, 2–10-flowered; peduncle 0.25– 2 mm long; rachis from almost nil to 14 mm long; subtending bracts spreading to ascending, spathulate to rhomboid, hooded, slightly fimbriate at apex, 0.75–1.5 mm long. Pedicel 0.5–3 mm long. Calyx obliquely campanulate, 2.5–3.5 mm long including the 0.75–1.25 mm receptacle; lobes subequal, very broadly to depressed-triangular, subacute to obtuse, ca. 0.5 mm long; upper 2 lobes slightly shorter, broader and are sometimes united higher than the lower 3; lower 3 lobes somewhat recurved. Corolla : standard depressed-ovate, retuse, subcordate, 5.5–6 × 6–7 mm including the ca. 1.5 mm claw, yellow marginally, grading to maroon at the centre; wings oblong to obovate, auriculate, may have lobes opposite on the abaxial margin, ca. 5–5.5 × 2 mm including the ca. 2 mm claw, maroon towards the apex; keel half broadly obovate with a ± obtuse apex, inflated, auriculate, saccate, 3 × 2– 2.5 mm including the ca. 2 mm claw, maroon in the upper half. Stamens strongly dimorphic: inner whorl of 5 with longer, compressed, inflexed filaments and subglobular, basifixed anthers with confluent thecae; outer whorl of 5 with shorter, broader, compressed filaments and larger, oblong, basifixed, 2-celled anthers; filaments free. Ovary narrow, tapered below to a short stipe and above to the inflexed style. Pod obliquely broadly obovate to obtrullate in outline, acute, style persistent, turgid, 4–6 × 3–4 mm, not dehiscing elastically; upper suture sigmoid; lower suture obtuse. Immature seed arillate. ( Figs 71 , 72 ).

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

Distribution:— Western Australia, in about five disjunct areas: near Kondinin–Narembeen area in the wheat belt; Gnarlbine Rocks south of Coolgardie; near Plumridge Lakes in the Great Victoria Desert; Bungalbin Hill in the Helena and Aurora Range; and the Ponton Creek–Queen Victoria Spring area east of Kalgoorlie. Also recorded from South Australia by a single fruiting specimen from north-western Eyre Peninsula, representing an extension of> 800 km to the known range of the species.

Conservation status:— Not currently of concern. However, the status of D. purpurascens is contingent on further genetic work that is needed to resolve its relationship to D. benthamii using molecular data. It might be reduced to a subspecies, or reduced to the Kondinin area population, whereas other populations (e.g. in the Gnarlbine–Coolgardie area, Helena and Aurora Range and Great Victoria Desert) could be included in D. benthamii . Daviesia purpurascens is uncommon in Kondinin area, where it is threatened by land-clearing.

Habitat:— Understorey of mallee eucalypts dominated by shrubs and Triodia . The type population near Kondinin grows on white sand-plains. In the Great Victoria Desert and at Gnarlbine it occurs on red sand-dunes, and in the Helena and Aurora Range the substrate is red-brown clay loam over banded ironstone. The vegetation at the Great Victoria Desert site is is Triodia -dominated with scattered mallee eucalypts and Callitris . At the South Australian site, it is on sandplain under mallee with Melaleuca .

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Selected specimens (25 examined):—WESTERN AUSTRALIA. Avon: Brookton – Corrigin Highway, 0.7 km N of Bullaring – Gorge Rock Road , 32°27’S, 117°59’E , G. S. Durell 258 & L. Kerrigan, 8 November 2000 ( CANB, MEL, PERTH). Coolgardie: East side of track, south of creek and main track crossing, c. 8 km NE of Bungalbin Hill, Aurora Range , 30°21’S, 119°42’E , N. Gibson 3352 & M Lyons, 24 July 1995 ( CANB, PERTH); ca. 6.5 km NE of Bungalbin Hill, Helena and Aurora Range, ca. 50 km NNE of Koolyanobbing, 30°21’S, 119°41’E , B. J. Lepschi 1994, 25 September 1995 ( CANB, PERTH, US); 13.7 km from Bullabulling along Great Eastern Highway towards Yellowdine, 31°06’S , 120°46’, M. D. Crisp 10743, 11 September 2010 ( CANB); near Gnarlbine , 31°09’S, 120°57’E , R. Helms s.n., 12 November 1891 ( AD 97552085 ). Helms : Ponton Camp to Ponton Swamp and Creek, Queen Victoria Spring Nature Reserve, 30°16’S, 123°19’E , D. J. Edinger 1079, 20 October 1995 ( PERTH). Roe : 40.75 km from Hyden along road to Kondinin, 32°31’S, 118°29’E , L. Sylvester s.n., August 1986 ( CANB 8700104 ); 33 km from Narembeen along road to Kondinin, 32°20’S, 118°18’E , M.D. Crisp 5517, 27 January 1979 ( CBG, PERTH); 18 km ENE of Kondinin , 32°27’S, 118°28’E , M.D. Crisp 6168 , J. M. Taylor & R. Jackson, 26 September 1979 ( CBG, NSW, PERTH); 41 km from Hyden to Kondinin, 32°21’S, 118°35’E , C.E.

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Woolcock D266 & D.T. Woolcock, 11August 1982 ( CANB). SOUTH AUSTRALIA. Eyre Peninsula: Yumbarra [Conservation Park], 3 km SW of Inila Rock Waters, 31°48’S, 133°24’E , C. O’Malley & A. C. Robinson NPWS 335 , 11 October 1987 ( AD) .

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Affinity:— Daviesia purpurascens differs from all other species of Daviesia by its non-triangular, turgid pods that do not dehisce elastically. Daviesia aphylla and D. benthamii can be similar to this species in vegetative morphology, but differ by their laterally compressed obtriangular pods that dehisce elastically, and also by their greenish-yellow, non-glaucescent branchlets and phyllodes. Molecular data indicate that D. aphylla belongs in a separate clade (VII.b, Fig. 1B ) and is more closely related to other species than to D. purpurascens . Daviesia aphylla also differs morphologically, having triangular pods and short phyllodes (<20 mm long) that are confined to the branchlet apex. However, the distinction between D. benthamii and some D. purpurascens populations is problematic. Plants at or near the type locality of D. purpurascens (in the region of Brookton, Narembeen and Dragon Rocks, WA) have relatively crowded phyllodes spreading more or less at right angles from the stem, are strongly purplish-glaucous and have the typical small, oblong pods ( Fig. 71 ) (e.g. Brooker 6329, Crisp 6168 and Durell 258). Other populations have sparser phyllodes that can be angled upwards ( Fig. 72 ) (e.g. Crisp 10743 from near Bullabulling, Lepschi 1994 and Gibson 3352 from the Helena and Aurora Range, and O’Malley & Robinson NPWS 335 from Eyre Peninsula, SA) or pods with intermediate morphology or colour (e.g. Forbes 1772 from near Carnamah, and Gibson 4399 from Marchagee, which are here included in D. benthamii ). DNA sequences of D. purpurascens from near the type locality (e.g. Crisp 6168) do not cluster with those from Gnarlbine Rock, near Coolgardie ( Fig. 1B ), but some of the latter could be hybrids with D. aphylla (see below). The relationship of D. aphylla , D. benthamii and D. purpurascens will be investigated using larger samples and in the meantime we continue to treat them as distinct species.

Hybrids. Daviesia aphylla × purpurascens . The population around a sand mine at Gnarlbine Rock, ca. 30 km SSW of Coolgardie, WA, includes plants resembling D. purpurascens (Crisp 5607–9, 5902–3, and 9396–7) but with vegetative parts varying from green to bluish grey, as well as plants resembling D. aphylla . The DNA sample from D. aphylla (Crisp 9398) yielded polymorphic ITS sequences, which when cloned, yielded a haplotype from each parental species and a third that is a likely recombinant.

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 71. Daviesia purpurascens, typical population. A. Fruiting branchlet. B. Inflorescence, flowers represented only by calyces. C. Flower. D. Pod. A, E from Crisp 6168; B, C from Brooker 6329 (type). Drawn by A.L. Prowse. Adapted from Crisp (1980a) with permission from the Board of the Adelaide Botanic Gardens.

FIGURE 72. Daviesia purpurascens, Gnarlbine population. A. Flowering branchlet. B. Inflorescence. C. Pod. A, B from Crisp 5902; C from Helms s.n. (AD 97552085). Drawn by A.L. Prowse.