Bidens alba var. radiata (Sch.Bip.) F.Ballard ex Melchert

Melchert, T.E. (1975) Phytologia 32(4): 295.

Shepherd's Needles; Spanish Needles

Herb to shrub 60-200 cm tall. Stems 4-angled.

Petioles 3-3.5 cm long, narrowly winged with hairs on the edge. Leaves simple or trifoliolate; simple leaf blades 7.3-8.5 x 4 cm, leaf blades on compound leaves 3-5-10 x 2.2-4.5 cm, leaflet stalks 3-20 cm long.

Inflorescence about 2.5 cm diam., flowers subtended by bracts about 4 mm long. Ray florets: About 5 per inflorescence, main lobe 8-veined, white, about 10 x 9, 2-3 -lobed but tubular at the base. Anthers nil. Ovary nil. Disk florets: Flowers 2-3 mm diam. Calyx, i.e. pappus, about 2 mm long. Corolla tube 2-5 mm long, lobes about 1 mm long. Anthers fused together, about 2 mm long, filaments about 3 mm long. Pollen orange-yellow. Ovary about 2 mm long, ovule solitary. Style about 5 mm long. Stigma hairy, about 2 mm long.

Fruits 9-12 mm long including the 2-barbed pappus, hairs or trichomes. Each fruit subtended by a bract about 6 mm long. Embryo white, 6-9 mm long, consisting mainly of cotyledons. Cotyledons about 4 mm long. Radicle about 3 mm long.

Features not available.

An introduced weed originally from tropical America, now naturalised in NEQ,CEQ and south into south eastern Queensland and north eastern New South Wales. Altitudinal range from 3-900 m. Found in edges of rainforest, in open forest and notophyll vine forest, woodland and in grassland.