Daviesia benthamii Meisner (1844: 48)

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

72. Daviesia benthamii Meisner (1844: 48) , Crisp (1980a: 271, partly), Crisp (1995: 1175, partly). Daviesia incrassata Sm. var. benthamii (Meisn.) Domin (1923: 34) . Type: ‘Swan River Drummond no. 241’. Holotype: BM; isotypes: E, G (2 sheets), MEL, OXF, P (2 sheets), W (2 sheets)

Bushy shrubs, 0.5–1(–2) m high, glabrous, dull green. Root anatomy anomalous (cord type). Branchlets from rather slender to thick and rigid, ± smooth when fresh, ribbed when dry. Phyllodes scattered, diverging at 45–60° (to 90° in specimens from the Shark Bay area), terete, pungent, inarticulate at the base, 10–80 (100) mm long and increasing in length down the branchlet but abruptly absent in about the lower third of the branchlets, 0.8–1.8 mm diam., obscurely ribbed when dry. Unit inflorescences 1 per axil, racemose, 4- or more-flowered; peduncle 0.5–4 mm long; rachis 1.5–12 mm long; subtending bracts spreading, oblong, apex acuminate, 0.5–1 mm long. Pedicels 1–7 mm long. Calyx 2.5–3.5 mm long including the 1–1.5 mm receptacle; lobes equal or upper 2 united slightly higher than the lower 3, all acuminate or upper 2 apiculate, 0.5–0.75 mm long. Corolla : standard transversely elliptic, retuse, 3–5 × 4–5.5 mm including the ca. 1.5 mm claw, yellow marginally with dull red infusion surrounding a central vertical, linear, dull yellow mark; wings obovate, rounded, incurved and partly enclosing the keel, auriculate, 4.5–5 × 1.75–2.5 mm including the ca. 1.5 mm claw, dull red grading to yellow or orange at the tips and margins; keel half transversely broadly elliptic, acute, auriculate, saccate, 4 × 1.5 mm including the 1.5 mm claw, dull red. 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, oblong, basifixed, 2-celled anthers; filaments free. Pod very broadly obovate to obtriangular, scarcely acute to slightly obtuse, strongly compressed, 5–7 × 4–6 mm, slightly rounded in outline, often with a pruinose bloom; upper suture slightly sigmoid; lower suture acute but broadly rounded. Seed not seen. ( Fig. 73 ).

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

Distribution:— Western Australia, extending from the Ningaloo Coast south to the Darling Range and east through the wheatbelt to around Merredin.

Habitat:— Grows in a variety of soils, from sand and gravelly clayey sand to clay and clay loam and gravelly laterite in eucalypt-dominated mallee or woodland (e.g. wandoo), shrubland with Acacia , Allocasuarina or Eremophila (Brown 1810: 518) and scattered eucalypts, or in Triodia -dominated hummock-grassland.

166 • Phytotaxa 300 (1) © 2017 Magnolia Press

CRISP ET AL.

A MONOGRAPH OF DAVIESIA

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Selected specimens (80 examined):— WESTERN AUSTRALIA. Carnarvon: 106 m [iles] along Exmouth Road, 23°20’S, 113°50’E, R . Blake S 2239, October 1972 ( PERTH); E of Mystery Well, Dirk Hartog Island , 25°39’S, 113°02’E, A. S . George 11582, 6 September 1972 ( CANB, PERTH); 14.5 km S of ‘ Gnaraloo’ homestead, 23°56’S, 113°31’E, A. S . George 10183, 3 September 1970 ( CANB, PERTH). Austin: Tallering Station, [ N of] Pindar , 28 km E of Mullewa, 28°29’S, 115°16’E, W. E . Blackall 674, 18 September 1931 ( PERTH). Irwin: Northern part of Oakagee Nature Reserve , near Olsen Road , N of Geraldton, 28°34’S, 114°40’E, L . Atkins 281, 17 August 2008 ( PERTH); 16 km S of Carnamah on Eneabba No. 1 Road , 29°48’S, 115°50’E, S. J . Forbes 1772, 23 October 1983 ( CANB, PERTH); ca. 5 km N of Morawa , 29°10’S, 116°01’E, H . Demarz 6890, 23 September 1978 ( CANB, PERTH); 32.5 km E of Coorow on Lathan Road , 29°45’S, 116°15’E, C . Chapman (99)77, 9 October 1977 ( CBG); 8 km WSW of Winchester , N end of location 8194, 29°48’S, 115°52’E, C . Chapman (120)77, 12 November 1977 ( CBG). Avon: Piawaning , 30°50’S, 116°23’E, M . D. Crisp 5480, 26 January 1979 ( CBG); 17 km NW of Quairading, 5.5 km W of Tongerung Well , 31°55’S, 117°17’E, M . D. Crisp 6193 et al., 27 September 1979 ( CBG, MEL, PERTH); Wongan Hills town site, Christmas Rock Walk Trail , 32°53’S, 116°43’E, M . D. Crisp 10048 & L. G . Cook, 23 September 2005 ( CANB); ca. 5 km N of Morawa , 29°10’S, 116°00’E, H . Demarz 6890, 23 September 1978 ( CANB, PERTH); Koolanooka Hills , 18 km E of Morawa, 29°13’S, 116°13’E, G. J . Keighery 2041 & J. J . Alford, 15 Aug 1990 ( CANB, PERTH); 14.5 km N of Dangin , 1 km S of T-junction, 31°55’S, 117°18’E, B. H . Smith 987, 30 September 1987 ( CBG, MEL); 50 km S of Mullewa , 28°57’S, 115°26’E, C. E . & D.T. Woolcock D 220, 22 August 1982 ( CANB). Coolgardie: Wadderin Rock , 32°00’S, 118°26’E, E. T . Bailey 354, September 1947 ( PERTH); ca. 20 km N of Muntadgin , 31°38’S, 118°39’E, P . Wilson 3459, 22 September 1964 ( AD). Darling: Toodyay – Bindoon road, ca. 31°30’S, 116°20’E, C. E . & D.T. Woolcock D220, 24 August 1982 ( CBG, MO) .

Affinity:— Previously, three subspecies were included in D. benthamii ( Crisp 1982b;1995) but new molecular data (see section on Species Delimitation above) strongly support its division into four cryptic species that are difficult but not impossible to diagnose morphologically ( D. benthamii s.s., D. aphylla , D. devito and D. schwarzenegger ). Daviesia aphylla (q.v.) was previously treated as D. benthamii subsp. acanthoclona (Crisp 1995) . It is distinguished from D. benthamii by having phyllodes absent or few (up to 6) and developed only near the branchlet apex, diverging at ca. 90°, short (<20 mm), and not increasing in length down the branchlet.

Some specimens from the Three Springs–Howatharra–Paynes Find area (WA) resemble D. aphylla morphologically by having few, short phyllodes near the branchlet apex (Atkins 281, Crisp 6316, Woolcock D235) or are leafless (Demarz 6890, Firth 711) but DNA sequences unambiguously place them with D. benthamii , not with D. aphylla . Specimens from near the WA south coast, in the vicinity of Jerramungup–Ravensthorpe and Fitzgerald River National Park, appear intermediate between D. benthamii and D. aphylla but most likely are a form of the latter (e.g. Kern et al. LCH 17265, Davis 2226, Gardner s.n. PERTH 05496233 and George 10535). Other specimens from the south coast (e.g. Ravensthorpe and Pallinup River) previously identified as D. benthamii subsp. benthamii are hybrids between D. aphylla and D. nematophylla . See discussion under D. nematophylla .

The former D. benthamii subsp. humilis ( Crisp 1982b) is here divided into two species, D. devito and D. schwarzenegger (q.v.). Daviesia devito extends through mallee districts of southern WA, SA, Vic. and into western NSW. It is a low (<1 m), spreading shrub with divaricate phyllodes developed all along the branchlets and is reliably distinguished from D. aphylla , D. benthamii and D. schwarzenegger by having minute, triangular, dark red stipules. Daviesia schwarzenegger is largely sympatric with D. devito . It differs from D. benthamii in having very robust phyllodes that are distributed all along the branchlets and scarcely increase in length (if at all) down the branchlet, rarely exceeding 3 cm. Daviesia benthamii has been confused with D. genistifolia in the past but the latter has basally articulate phyllodes, larger flowers (e.g. standard 4.5–5.5 × 5–6.5 mm) and larger pods (8–11 × 4– 8 mm).

Hybrids:— Daviesia benthamii × nematophylla . See discussion under D. nematophylla .

VII.b. D. aphylla Clade

Figures

FIGURE 73. Daviesia benthamii. A. Flowering branchlet with short racemes. B. Short inflorescence. C. Pod. D. Fruiting branchlet with long racemes. A from Drummond 241 (type); B from Crisp 6193; C from Crisp 5480; D from George 10183. Drawn by A.L. Prowse. Adapted from Crisp (1995) with permission from CSIRO Publishing.