Daviesia longifolia Benth.

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

16. Daviesia longifolia Benth. in Lindley (1839: 14), Bentham (1864: 78), Crisp (1987a: 251), Crisp (1991a: 255), Crisp (1995: 1208), Wheeler et al. (2002: 744). Type: Swan River, Drummond 1st collection, 1839. Holotype: K; isotype: CGE

Daviesia chordophylla Meisner (1844: 48) , Bentham (1864: 78). Type: ‘Swan River [Drummond] No. 239, ex parte, et 240’. Lectotype ( Crisp 1991a): Drummond 240, ex Herb. Shuttleworth (BM); isolectotype: CGE, G (3 sheets), K (2 sheets), MEL 77812, OXF, P (2 sheets), W (2 sheets). Syntype: Drummond 234 (239?), partly, ex Herb. Shuttleworth (BM); isosyntype: ex Herb. Meisn. (NY).

Bushy, multi-stemmed shrubs, 0.3–0.7 (1.5) high, 1–3 m broad, glabrous. Root anatomy normal (unistelar). Branchlets weak, often tangled, compressed or terete, angular with prominent ribs. Phyllodes scattered, ascending, linear, flat to terete, sinuous or gently curved, apically acute or obtuse, mucronate, basally inarticulate, decurrent, to 250 × 1–10 mm, with 6–many parallel ribs, greyish green, often reduced in size toward branchlet apex. Unit inflorescences 1 or more per axil, racemose, 4–15-flowered (or fewer by early bud fall), usually with 2(–4) flowers grouped at the apex; peduncle (4–) 10–17 mm long; rachis (0–)6–28(–150) mm long; subtending bracts mostly

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appressed, triangular or ovate, keeled, often with a small lobe on each margin, minutely fimbriate, ca. 1 mm long. Calyx 3–4 mm long including the ca. 1 mm receptacle to which it is contracted, ventricose above, smooth or with 5 (10) obscure ribs; upper 2 lobes recurved, united into a truncate, retuse lip; lower 3 lobes shorter than upper 2, very depressed-triangular, apiculate, ca. 0.5 mm long, apex tinged purple. Corolla : standard depressed-ovate to very broadly ovate, emarginate, truncate at base, 6.5–9 × 6.5–8.5 mm including the 2–3.5 mm claw, yellow infused with dark red towards the centre, with an intense yellow oblong mark at centre; wings obovate, rounded and incurved at apex, auriculate, 6.5–8 × 2–2.5 mm including the 2–3 mm claw, dark red; keel half very broadly obovate, ± acute, scarcely auriculate, saccate, 4.5–6 × 1.5–2 mm including the 1.5–2.5 mm claw, deep red at tip. Stamens strongly dimorphic: inner whorl of 5 with slightly compressed filaments and versatile, very broadly ovoid anthers with confluent thecae; outer whorl of 5 with strongly compressed filaments and basifixed, transversely broadly obloid, 2-celled anthers; filaments free. Pod obliquely shallowly obtriangular, acuminate, compressed, 7–12 × 4–7 mm, with slightly raised, reticulate venation, grey-brown; upper suture sigmoid; lower suture acute. Seed obovoid to ovoid, ca. 3.5 mm long, ca. 2 mm broad, ca. 1 mm thick, pale greenish brown with a little mottling; aril ovoid, swollen towards base, 0.75–1.5 mm long, pale yellow. ( Fig. 18 ).

Flowering period:— August in the north to December in the south. Fruiting period: October in the north to November further south.

Distribution:— Western Australia, from Eneabba south to the Blackwood and Gordon Rivers, and east to Yealering, Tarin Rock and Katanning in the southern wheatbelt.

Habitat:— Grows in sand or gravelly clay soil derived from laterite. Associated vegetation is most commonly heath dominated e.g. by Grevillea R.Brown ex Knight (1809 : xvii), Banksia or Allocasuarina . Also in open forest dominated by Eucalyptus marginata and Corymbia calophylla or in woodland with E. wandoo Blakely (1934: 112) .

Selected specimens (53 examined):— WESTERN AUSTRALIA. Irwin: 42 km W of Winchester , 29°48’S, 115°30’E, C . Chapman (113)77, 23 October 1977 ( CBG, PERTH); 20 km S of Eneabba , 29°58’S, 115°13’E, C . Chapman (114)77, 23 October 1977 ( CBG, MEL, PERTH); Green Head Road , 30°04’S, 115°19’E, M . D. Crisp 6222 et al., 29 September 1979 ( CBG, PERTH). Avon : 3 km SSW of Wedin, 33°00’S, 117°41’E, M . D. Crisp 6148 et al., 26 September 1979 ( CBG, PERTH). Darling: 93 km NNE of Perth along Northern Highway , 31°15’S, 116°10’E, C . Chapman (122)77, 21 November 1977 ( CBG, PERTH); Mt Lesueur , 30°10’S, 115°12’E, R . D. Royce 7727, 4 November 1962 ( PERTH); Blackwood River , J . Forrest s.n. ( MEL 81161–4 ); 80.8 km SE of Perth , 32°17’S, 116°34’E, A. S . George 7369, 25 November 1965 ( AD, CANB, NSW, PERTH); Harvey, 33°05’S, 115°54’E, Miss Lambert 112, December 1900 ( PERTH); Kalamunda, Darling Range , 31°58’S, 116°03’E, A . Morrison s.n., 18 December 1901 ( CANB 336586 , E, PERTH 2729806 ); Preston River , 33°32’S, 116°02’E, F . Mueller s.n., 8 December 1877 ( MEL 81300 ); Gordon River , 34°14’S, 117°14’E, A. F . Oldfield 499 ( MEL); Sussex , 33°53’S, 115°44’E, L . Preiss 1184, 23 December 1839 ( MEL, S); Muchea , 31°35’S, 115°58’E, R . D. Royce 4718, 2 December 1953 ( PERTH) .

Affinity:— Daviesia longifolia is very similar to both D. costata and D. pauciflora . Daviesia costata has ten prominent ribs on the calyx and the lobes are uniform, whereas in D. longifolia the calyx is either ribless or has five obscure ribs and the upper two lobes are outcurved and larger than the lower three. In D. pauciflora the calyx lobes are all alike and not outcurved. The profile of the calyx of D. longifolia also differs from that of D. pauciflora in being ventricose on the upper (adaxial) side.

Another character distinguishing these two species is the size of the inflorescence. In D. pauciflora , the racemes are usually shorter (rachis usually 0–4 mm long, peduncle usually 1–13 mm long) and bear fewer flowers (usually 1–4). In addition, D. longifolia differs in having irregularly curved or sinuous phyllodes, a truncate base to the standard, parallel wings that often overlap at the apex and smaller pods (11–14 mm long in D. pauciflora ).

Variation:— This is a variable species, mainly in the width and cross-section of the phyllodes. The variation shows a certain amount of geographic pattern but is not sufficiently strong to justify the recognition of infra-specific taxa.

Plants occurring in the Mt Lesueur to Eneabba region tend to have broader phyllodes (e.g. Chapman (113)77 and Royce 7727). These range in width from 2.5–10 mm but are usually> 4 mm wide. Farther south the phyllodes are generally less than 4 mm broad, although in specimens from Blackwood River, at the southern limit of the species’ range (Forrest s.n., MEL), they are up to 6 mm broad.

A MONOGRAPH OF DAVIESIA

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Towards the central and eastern portion of the range, i.e. in the vicinity of Boddington, Yealering and Harrismith, the phyllodes become terete (e.g. Crisp 6148). This is the form represented by the synonym D. chordophylla . A number of specimens from the Perth–Pinjarra region (e.g. George 7369 and Mueller s.n., MEL) show a continuous transition from this terete-leaved form to the typical form with compressed phyllodes.

Typically, D. longifolia has eight or more ribs per phyllode. However, some southern specimens have phyllodes with an oblong cross-section and three parallel ribs visible on each face (e.g. Preiss 1184 and Forrest s.n., MEL). Closer inspection of these specimens reveals that there are two ribs at each margin, i.e. one at each angle of the oblong cross-section. With the midribs on the upper and lower surface, this makes a total of six ribs per phyllode. These phyllodes may be confused with those of D. costata , in which three ribs are visible on both the adaxial and abaxial faces. In fact, the phyllodes of D. costata have a total of only four ribs because there is a single rib at each margin. The phyllodes of D. costata are flat when broad and tetragonous in section when narrow. See the ‘Affinity’ section above for additional differences between D. longifolia and D. costata .

Figures

FIGURE 18. Daviesia longifolia. A. Flowering branchlet. B. Broad phyllode. C. Terete phyllode. D. Inflorescence (flowers represented by calyces only). E. Flower with bract. F. Calyx opened out, upper lobes at left. G. Standard. H. Wings. I. Keel. J. Same, opened out. K. Pod. A from Morrison s.n. (CANB 336586); B, D–J from Crisp 6222; C from Crisp 6148; K from Chapman (114)77. Drawn by A.L. Prowse and D. Fortescue. Adapted from Crisp (1991a) with permission from CSIRO Publishing.