Cissus oblonga (Benth.) Planch.

Planchon, J.E. in Candolle, A.L.P.P. de & Candolle, A.C.P. de (1887) Monographiae Phanerogamarum 5 : 517.

Vine, Smooth Water; Smooth Water Vine

Vine stem diameters to 20 cm recorded. Sapwood surface often corrugated. Blaze marked with broad pale stripes and narrow darker stripes.

Stipules caducous, about 8-10 x 2-2.5 mm, clothed in prostrate brown hairs. Leaf blades about 3-11 x 1.5-6 cm, petioles about 1.2-3 cm long. Lateral veins 10-13 on each side of the midrib. Two large glands or gland-like domatia occur on the basal pair of lateral veins near the midrib. Similar structures may also be apparent on other veins. Teeth, if present, usually towards the apex of the leaf blade. Oil dots streaky. Lateral veins forming loops inside the blade margin. Tendrils simple, unbranched.

Inflorescence about 2-4 cm long. Pedicels about 2-3 mm long. Calyx cup-shaped, calyx lobes very short, rounded. Petals about 2 x 1 mm, apex hooked. Staminal filaments about 1 mm long. Style about 0.6 mm long.

Fruits black when ripe, globose, about 10-13 mm diam., surface marked with white spots. Pericarp purple, staining the fingers when dissected. Seeds 1-4 per fruit, variable in shape, about 7-9 mm long. Testa surrounded by a fleshy green layer. Endosperm ruminate with deep intrusions of the testa. Embryo about 1.5-2 mm long, cotyledons wider than the radicle.

Cotyledons almost triangular to elliptic, about 20-28 x 15-22 mm, petioles about 3-7 mm long, grooved on the upper surface. First pair of leaves ovate, apex mucronate, base cordate, margins toothed. Leaf blades about 30 x 35 mm. Stems, petioles, buds and upper and lower surfaces of the leaf blades clothed in brown prostrate hairs. At the tenth leaf stage: leaf blade about 7-11 x 3.5-6.5 cm, domatia (pits or swollen glands) present in the axils of the main lateral veins. 'Oil dots' elongated. Midrib raised on the upper surface. Petiole about 17-20 mm long. Stipules caducous, about 5-10 mm long. All plant parts clothed in medifixed hairs at least when young. Seed germination time 110 to 198 days.

Endemic to Queensland, occurs in NEQ, CEQ and southwards to south-eastern Queensland. Altitudinal range in NEQ from near sea level to 900 m. Usually grows in vine thickets and monsoon forest, sometimes on rock outcrops, sometimes in the drier more seasonal rain forests.