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Scale bar 10mm. Copyright CSIRO
Female flowers. Copyright CSIRO
Male flowers. Copyright CSIRO
Leaves and female flowers. Copyright CSIRO
Male flowers. Copyright Barry Jago
Dioscorea transversa R.Br.
Brown, R. (1810) Prodromus Florae Novae Hollandiae: 295. Type: Northern Australia, R. Brown; holo: BM?; iso: NSW.
Dioscorea punctata R.Br., Prodromus Florae Novae Hollandiae: 294(1810), Type: East coast of Australia; R. Brown; holo: BM.
Long Yam; Yam, Native; Native Yam; Yam, Long; Yam
A slender vine not exceeding a stem diameter of 2 cm. Stems twining to the right.
Leaf blades about 4.5-14 x 3-12 cm. Petioles about 2-6 cm long, thickened just prior to their junction with the twig. Elongated oil dots visible with a lens. Leaf blades 5-veined or obscurely 7-veined at the base. Small globular bulbils present in some leaf axils.
Male flowers: Spikes about 6-7 cm long, usually about 3-5 spikes in each leaf axil. Flowers sessile, +/- globose, about 1.5 mm diam. Tepals in two similar whorls, each tepal about 1.5-2 mm long. Stamens about 0.5 mm long, fused together to form a very short column +/- attached to the base of the tepals. Female flowers: Spikes about 1.5-2.5 cm long, usually 1 or 2 spikes in each leaf axil. Flowers pleasantly perfumed, sessile, about 1.2 mm diam. Tepals in two similar whorls, the outer tepals slightly larger. Tepals about 0.8-1.1 mm long. Hypanthium 3-angled, about 2 mm long. Six minute staminodes or nectary glands visible around the base of the ovary. Style 3-armed, the arms reflexed. Ovules 2 per locule.
Fruits 3-winged, produced in pendulous clusters. Each fruit about 15-20 x 23-26 mm. Wings rounded, about 14-16 x 12-14 mm. Seeds about 6 per fruit. Seed + wing about 15-19 x 11-16 mm. Embryo located on the margin of the seed. Embryo about 0.8-1 mm long, paddle-shaped to obpyriform. Radicle shorter than the 'cotyledon'.
First leaf cordate to orbicular, about 25-35 x 25-35 mm, base deeply cordate. Upper surface dark green, lower surface red to purple. About 7 depressed veins radiate from the base of the leaf blade. Petioles red, about 25-35 mm long, longitudinally ribbed with 4 or 5 ribs.
Distribution and Ecology
Endemic to Australia (?), occurs in WA, NT, CYP, NEQ and southwards as far as south-eastern New South Wales. Altitudinal range in northern Australia from near sea level to 1100 m. Grows in open forest, wet sclerophyll forest, rain forest and gallery forest.
A decoction of this small native yam was used by Aborigines of the Tully (NEQ) district as a application for skin cancers. Cribb (1981).