A reddish stemmed, 15-60 cm tall, annual herb with alternate, triangular leaves and triangular pyramid shaped seeds.
Description:
Cotyledons:
Two. Kidney shaped, large. Tip round. Edges smooth and undulating. Base indented. Petiole longer than blade. Hairless. Base of stem red.
First leaves:
Triangular. Tip round. Edges lobed and undulating. Base indented. Prominent veins. Hairless.
Leaves:
Alternate, triangular.
Stipules - (Ochrea) Brown, flat topped, smooth edged, hyaline, not ciliate on the upper edge
Petiole - Lower leaves have petioles, upper ones have none. No nectaries.
Blade - Triangular, 30-70 mm long by 30-65 mm wide. Tip pointed. Edges smooth, Base flat to indented.
Stems:
Erect, up to 500 mm tall, few branches
Flower stem - Hairy stalk arsing from the leaf axil.
Flower head:
Flowers in short, compact clusters arising from leaf axils. Individual flowers on long, hairy, non articulate stalks.
Flowers:
Small pink to white 5 petalled, 3 mm diameter flowers. Bisexual.
Ovary - Superior.
Style - 3 branched
Stigma - Small, head like, smooth.
Petals - (Perianth) 5 segments. White to pink, 1.5-3.5 mm long.
Stamens - 8
Anthers - versatile.
Fruit:
Nut or achene loosely held in by the sepals.
Seeds:
Black to brown. Triangular pyramid shape. 5-6 mm long by 3-5 mm wide. Much larger than the perianth (petals). Tip pointed, Edges flattish, smooth, almost winged. Base flattish with stalk remnant. Surface mottled, smooth and dull.
Roots:
Taproot.
Key Characters:
Leaves simple.
No petiolar nectaries.
Ochrea (sheaths of fused stipules) present around the petiole and stem, entire, tubular, soon disintegrating, pale brown, upper margin not ciliate.
Flowers bisexual.
Stigmas capitate, smooth.
Perianth segments 5.
Anthers versatile.
Nut much exceeding the perianth segments.
Adapted from Gwen Harden.
Biology:
Life cycle:
Annual. Seeds germinate from spring to summer.
Physiology:
Reproduction:
By seed.
Flowering times:
Spring.
Seed Biology and Germination:
Vegetative Propagules:
Hybrids:
Allelopathy:
Population Dynamics and Dispersal:
Spread by seed and intentional planting.
Origin and History:
Western and central Asia.
Distribution:
ACT, NSW, NT, QLD, SA, TAS, VIC, WA.
Habitats:
Climate:
Temperate, sub tropical.
Soil:
Plant Associations:
Significance:
Beneficial:
Cultivated for grain.
Detrimental:
Weed of disturbed areas.
Toxicity:
Not recorded as toxic.
Symptoms:
Treatment:
Legislation:
None.
Management and Control:
Grazing or mowing normally provides adequate control.
Thresholds:
Eradication strategies:
Spray small patches with a mixture of 1 litre of Tordon 75-D in 100 L water before flowering when actively growing annually as required.
Herbicide resistance:
None reported.
Biological Control:
Related plants:
None in the same genus in Australia.
Docks, Sorrel, Spiny Emex, Wireweed, Bindweed and Knotweed are in the same family.
Plants of similar appearance:
Dock, Tree Hogweed
Fat Hen has no ochrea.
References:
Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).
Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).
Harden, Gwen J. (1991). Flora of NSW. (Royal Botanic Gardens, Sydney). Volume 1. P288. Diagram.
Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).
Moerkerk, M.R. and Barnett, A.G. (1998). More Crop Weeds. R.G. and F.J. Richardson, Melbourne. P112. Diagrams. Photos.
Acknowledgments:
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.