Australian Tropical Rainforest Plants - Online edition
Causonis maritima (Jackes) Jackes
Jackes, B.R. (2020) Telopea 23: 69-71.
Coastal Water Vine; Vine, Coastal Water
Vine stem diameters to 7 cm recorded.
Leaflet blades about 5.5-10 x 4.5-8 cm, leaflet stalks about 0.7-2 cm long. Middle leaflet normally larger than the lateral leaflets and borne on longer stalks. Lateral veins about 9-14 on each side of the midrib. Leaflet blade margins with about 9-14 serrulate to crenate teeth on each side. Tendril leaf-opposed and usually 3-armed. Leafy twigs and larger twigs elliptic rather than circular in transverse section. Stipules caducous, leaving a broad scar.
Inflorescence leaf-opposed or axillary, each inflorescence about as long as the compound leaves. Flowers about 3-4 mm diam. Calyx cup-shaped, hairy, lobes about 0.1 mm long. Petals about 2 mm long, outer surface hairy, inner surface glabrous. Staminal filaments about 1.1-1.5 mm long, anthers about 0.5 mm long. Disk cream-coloured, lobes about as high as the staminal filaments. Ovary embedded in the disk. Ovules 2 per locule.
Fruits globular or depressed globular about 12 x 9-15 mm. Seeds up to 4 per fruit, each seed shaped like a quarter of a pear or sphere sliced vertically through the central axis. Each seed about 5-7 x 5-6 mm. Testa intruding into the endosperm by way of only one intrusion. Embryo about 1-1.1 mm long. Cotyledons wider than the radicle.
Cotyledons 3-veined, large, about 22 x 17 mm, petiole about 4 mm long. First leaf trifoliolate, middle leaflet about 28-37 x 18-23 mm, lateral leaflets about 25-30 x 13-14 mm. At the tenth leaf stage: leaflet margins toothed, middle leaflet usually longer (larger) than the lateral leaflets. Stipules triangular, about 1 mm long. Tendrils produced about the 9th or 10th leaf stage. Tendrils usually 2-branched.
Occurs in NT, CYP and NEQ. Altitudinal range from near sea level to 100 m. Usually grows in gallery forest or riparian forest often near permanent water. Also occurs in New Guinea and other parts of Malesia and the Pacific islands.