Gahnia sieberiana Kunth

Kunth, K.S. (1805) Enumeratio Plantarum 2: 332. Type: Sieb. herb. Novo-Holl. n. 536.

Gahnia, Small-seeded; Sword Grass; Small-seeded Gahnia; Sawsedge; Red Fruited Saw Sedge; Saw Sedge

Essentially a herb with an underground rhizome but leaves can attain a height of 2 m or more.

Leaf blade about 40-120 cm long. Leaf margins very finely toothed (visible with a lens) so that the leaves can cut the hands of careless or over enthusiastic collectors and children. Teeth also present on the upper surface of the leaf blade. Leaves without a midrib.

Spikes 2-flowered, bisexual flowers in the upper half and male flowers in the lower half. All male flowers open first and together on the inflorescence then all upper flowers open first as female then later as male so that the plant appears male or female. Flowers with no perianth. Pairs of flowers contained in about 6-10 tight bracts (glumes). Styles or anthers protruding from the glumes.

Fruits shiny reddish brown, about 3 x 1.5 mm and very difficult to crush between the teeth. Embryo small (about 0.5 mm long) shaped like an elongated rugby football.

First pair of leaves about 40-50 x 0.5 mm with minute teeth along the margin at least towards the apex. At the tenth leaf stage: leaf blade radicle and sheathing, about 38-46 x 0.6-0.7 cm, margin serrate. Lower surface of the leaf blade glabrous, upper surface with short pale hairs. Venation longitudinally parallel. Petiole very short to sessile.

Occurs in CYP, NEQ, CEQ and southwards as far as Victoria and Tasmania. Altitudinal range from near sea level to 1200 m. Grows in disturbed areas in well developed rain forest on a variety of sites. Also occurs in Malesia.

Food plant for the larval stages of several species of Skipper Butterflies. Common & Waterhouse (1981).