Daviesia rubiginosa Crisp (1995: 1230)

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

83. Daviesia rubiginosa Crisp (1995: 1230) . Type: Western Australia, Roe, 19 km E of Peak Charles , 32°46’S, 121°17’E, M. D. Crisp 5992, J . Taylor & R . Jackson, 20 September 1979. Holotype: CBG ; isotypes: K, L, MEL, NSW, PERTH . Paratypes: Western Australia, Coolgardie District , 2 km NE of Mt Hampton, 31°55’S, 119°05’E, M . D. Crisp 5564, 29 January 1979 ( CBG, MEL, NSW, PERTH); Yellowdine, c. 32 km E of Southern Cross, Paul G . Wilson 3527, 23 September 1964 ( AD, PERTH)

A MONOGRAPH OF DAVIESIA

Phytotaxa 300 (1) © 2017 Magnolia Press • 189 Broom-like shrubs, to 2 m tall, glabrous to glaucous. Root anatomy with anomalous secondary thickening (cord type). Branchlets erect, terete, lightly pruinose, becoming reddish or purplish with age. Phyllodes scattered, erect, linear to terete, mucronate, when linear obtuse or truncate at apex and and attenuated to the obscurely articulate base, 30–250 mm or longer, 0.5–1 mm diam. when terete, to 4 mm broad when linear, smooth when fresh or with numerous longitudinal veins when dry that anastomose in linear phyllodes, glaucous. Seedling phyllodes obovate, retuse, tapering to base, 55–130 × 6–13 mm, glaucous. Unit inflorescences 1(2) per axil, racemose, 2–4-flowered; peduncle ca. 1 mm long; rachis 1–8 mm long; subtending bracts spreading widely, spathulate, 2–2.5 mm long, caducous leaving a rim at pedicel base. Pedicel 3–5.5 mm long. Calyx 4–4.5 mm long including the ca. 1 mm receptacle; lobes ± equal, gently recurved, acuminate, each with a central rib. Corolla : standard transversely elliptic, emarginate, 6–7 × 8–9 mm including the 1.5–2 mm claw, with 2 calli at the base of the lamina, orange-yellow with a large red ring surrounding the bright yellow centre; wings spathulate, rounded and incurved at apex to enclose the keel, ca. 6 × 3 mm including the 2 mm claw, bright red; keel acute, abaxially rugose, 5 × 2 mm including the 1.5 mm claw, very pale pink (almost white). 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; vexillary stamen with filament channelled, embracing gynoecium, dilated upwards. Pod obliquely shallowly obtriangular, acuminate, pungent, compressed, 10–12 × 6–7 mm, red-brown; upper suture sigmoid; lower suture acute. Seed not seen. ( Fig. 83 ).

Flowering period:— August to October. Fruiting period: October and November.

Distribution:— Western Australia, eastern fringes of the wheatbelt (and beyond), from Chiddarcooping Hill south-east to the Mt Buraminya area, east of Esperance.

Habitat:— Yellowish clayey granitic sand, sometimes with gravel, or sandy loam over granite or ironstone in heath commonly dominated by Allocasuarina campestris ( Diels 1904: 126) Johnson (1982: 74) and broombush species of Melaleuca .

Selected specimens (15 examined):— WESTERN AUSTRALIA. Avon: Ca. 65 km SSW of Southern Cross, 2 km NE of Mt Hampton , 31°55’S, 119°05’E, M . D. Crisp 5564, 29 January 1979 ( CBG, MEL, NSW, PERTH); Holleton, near Merredin , 31°57’S, 119°01’E, A. W . Miller (per J. A. C. Smith) s.n., 30 October 1973 ( PERTH 5212200 ). Coolgardie: Yellowdine , 31°18’S, 119°39’E, P . Wilson 3527, 24 September 1964 ( AD, PERTH); ibid., H . Demarz 7181, 14 November 1978 ( PERTH). Roe: 19 km NE of Peak Charles along road to Norseman , 32°46’S, 121°17’E, M . D. Crisp 5993, et al., 20 September 1979 ( CBG, NSW, PERTH); NW slopes of Mt Ironcap , 32°21’S, 119°40’E, P. S . Short 1702, 12 September 1982 ( MEL); Holt Rock , 32°41’S, 119°25’E, M . D. Crisp 9001 & W . Keys, 22 October 1997 ( CBG, PERTH) .

Affinity:— Daviesia horrida is probably the closest relative of D. rubiginosa ( Fig. 1B ). These species are very similar in all reproductive parts, as well as in the unusual anastomosing venation. Also, both have strikingly different ontogenetic stages in their vegetative morphology. In D. horrida the phyllodes are reduced to scales in the upper branchlets, whereas the upper phyllodes of D. rubiginosa become terete but remain elongate. Daviesia horrida may be distinguished readily by its rigid, divaricating, spinescent branchlets, acute phyllode apex, larger racemes (rachis 2–20 mm long, flowers 3–10) and persistent bracts.

Variation:— Daviesia rubiginosa is an odd species, with apparently plastic phyllodes, varying even on a single plant. This is the reason that papatypes were designated. It appears that the linear phyllodes may represent an earlier ontogenetic stage and terete phyllodes a later stage. Nevertheless, plants with entirely linear phyllodes are fully fertile, perhaps a result of heterochrony. An alternative explanation may be that linear phyllodes are an adaptation to xeric habitats—specimens from more inland, drier sites (e.g. Crisp 5564, Wilson 3527) have mostly terete phyllodes. However, plants seen from such sites were also larger, and therefore probably older at the time of collection, than plants collected nearer the coast (such as the holotype).

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 83. Daviesia rubiginosa. A. Flowering branchlet with flat phyllodes. B. Terete phyllode. C. Inflorescence. D. Pod. A, C from Crisp 5992 (type); B, D from Demarz 7181. Drawn by A.L. Prowse. Adapted from Crisp (1995) with permission from CSIRO Publishing.