Vitex benthamiana Domin

Sengun, S., Ingrouille, M., Paton, A. & de Kok, R. P. J., 2024, Taxonomic revision of the Vitex trifolia complex (Lamiaceae), Blumea 69 (2), pp. 93-121 : 98-102

2. Vitex benthamiana Domin — Fig. 3 , 4 ; Map 2

Vitex benthamiana Domin (1928) 560; Munir (1987) 61. — Lectotype (designated by Munir 1987): Domin 8164 (PRA n.v.), Australia, Queensland, Cloncurry.

Vitex trifolia L. var. parviflora Benth. (1870) 67; Munir (1987) 61. — Type: Landsborough s.n. (holo K [ K000223177 ];iso MEL [ MEL98012 ]), Australia, Queensland, Gulf of Carpentaria, possibly near Albert River .

Shrub or small tree, 1.6–4 m high. Bark smooth to slightly fissured, grey. Leaves (1- or) 3-foliolate; petioles 0.4–5.5 cm long. Leaflets: blades narrowly elliptic to lanceolate, apex acuminate, rarely acute, base attenuate when trifoliate, rounded or cuneate when unifoliate, margin entire, upper surface green, lower surface whitish; aromatic when bruised; secondary veins 9 –14 per side, slightly prominent, visible on both surfaces; terminal leaflets 2.2–10.1 by 0.7–3.1 cm; terminal petiolules (0–)0.1–0.9(–1.9) cm long; lateral leaflets 1.4–9.3 by 0.3– 2.6 cm, sessile. Inflorescence terminal, consisting of lateral cymes in dense clusters with persistent flowers; axis 5.4–18 cm long, smooth; bracteoles ovate to linear, up to 2(–3.8) mm long, patent, usually persistent, drying the same colour as inflorescence. Calyx glands many; tube 1.7–2.5 mm long; lobes 2–7 by 1–9 mm, lobe apex acute; flowering calyx 2–3 mm diam; fruiting calyx 5–6 mm diam, patent to erect, covering most of the mature fruit. Corolla light or pale mauve to lilac; glands few; tube 1.7–7 mm long; anterior lip spathulate, 2–5.5 by 2.5–5 mm, apex round to acute, anterior corolla lip with a semi-circular area of hairs at the corolla mouth; lateral lobes 2–3 by 2–2.5 mm, apex round, erect; posterior lip lobes 1.2–2.2 by 1–2 mm, apex acute, erect. Stamens: filaments 3–5.8 mm long, slightly didynamous to equal, glabrous, inserted at half to lower 1/3 of the corolla tube; anthers c. 1 mm long. Ovary 1–1.5 mm diam, glabrous, glands many, covering the apex; style 3.6–7 mm long; stigma lobes 0.2–0.7 mm long. Fruit dried broadly obovoid to globose, 2.2–6 by 2.2–6.2 mm, glabrous.

Distribution — Australia (Queensland: from Cloncurry and Mt Isa along several rivers to Burketown on the Gulf of Carpentaria).

Habitat & Ecology — Along seasonally dry or permanently flowing rivers and creeks, in Eucalyptus woodland with an understory of Acacia hemsleyi Maiden ( Fabaceae ), Eucalyptus camaldulensis Dehnh. ( Myrtaceae ), E. microtheca F.Muell. , Melaleuca argentea W.Fitzg. ( Myrtaceae ), M. trichostachya Lindl. and Pandanus aquaticus F.Muell. ( Pandanaceae ). Soil: sandy or alluvial black soils or brown clay, at 125–300 m altitude. Flowering: April to August, fruiting: April to August.

Conservation status — Least concern (LC) as it is common throughout its range and there are no known threats ( Sengun 2017).

Notes — 1. This Queensland endemic species has the most restricted range of all species in the complex, but where it occurs it is reported to be common. Its leaves are mostly trifoliolate like V. trifolia , but it differs from V. trifolia by its narrow lanceolate leaflets and cymes in dense clusters.

2. It has not been possible to see the type or an image of V. benthamiana , which is housed at PRA. However, Munir (1987) reports to have seen it when he selected it as a lectotype .

Figures

Map 2 Natural distribution of Vitex benthamiana Domin.

Fig. 3 Vitex benthamiana Domin. a. Habit; b. part of inflorescence;c. flower,side view;d. calyx open, adaxial; e. corolla open; f. style;g. ovary;h. fruit in calyx; i. fruit in cross-section (a: Perry 1061; b–d: Gittins s.n.; e, f: Puttock 14410; g: Gittins s.n.; h, i: Halliday 428; all K). — Drawing by Juliet Beentje.

Fig. 4 Vitex benthamiana Domin. a. Habitat; b. flower; c. mature inflorescence; d. leaves; e. infructescence detail with dried fruits; f. detail of bark. — Photos by R. de Kok.