Family: - Amaranthaceae.Names:
Summary:An erect, stout, annual herb, 700 mm to 2000 mm tall, with more or less horizontal branches from the base and along the length of the stems. Many small, green flowers are packed into long, conical spikes at the ends of branches or from the leaf axils.
First leaves:The leaves develop in pairs, the first being 12 to 25 mm long in the blade with a petiole 10 to 20 mm long. They are hairless, but have a few short hairs on the petiole. The first leaves have a distinctive apical notch.
Leaves:Later leaves have a typical kite shape. The plant does not form a rosette.
Stems:The stems are stout, circular or oval in cross section and solid with shallow longitudinal grooves. Hairless or with sparse, erect, fine hairs particularly on the upper stems. The stem is pale green and frequently reddish in colour though the colour may develop on one side only.
Flower head:The inflorescences are terminal and axillary, consisting of large numbers of flowers packed tightly into bristly, stout, conical spikes usually with few branches.
Flowers:The individual flowers are 2 to 3 mm in diameter, sessile, and green with five petals. Separate male and female flowers on the same plant. Female flowers more numerous than the male flowers.
Fruit:About 2 mm long. More or less wrinkled. Opens along a transverse line around the middle.
Seeds:Single. Black. Shiny. Broadly elliptical and 1-1.5mm long.
Seed Biology and Germination:Vegetative Propagules:
Distribution:NSW, SA, TAS, VIC.
Habitats:Frequently found around stockyards.
Detrimental:It is principally a weed of stock yards, disturbed areas, orchards, hops and home gardens. It is a serious weed of summer crops.
Toxicity:Not reported as toxic, but other closely related species can be toxic.
Management and Control:Thresholds:
Plants of similar appearance:In parts of the North-West of Tasmania, a closely allied species Amaranthus retroflexus L. (Redroot, sometimes called 'Redshank' locally) occurs as a weed in vegetable crops. It is very similar in general appearance to Powell's Amaranth but has stems densely covered in woolly hairs. Common names applied to other species of Amaranthus, and occasionally used for the Tasmanian species, include Prince of Wales Feathers and Pigweed. This species has, for a long time, been incorrectly called Amaranthus hybridus L. in Tasmania.
References:Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P71. Photo.
Acknowledgments:Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.