Native Amaranth

Amaranthus interruptus R.Br

Family: Amaranthaceae.

Names:

Native Amaranth - because it is an Australian native plant. Amaranth is from the Greek meaning "not to wither" referring to the persistent flower spike.

Summary:

An annual, erect herb. Scentless.

Description:

Cotyledons:

Two.

Leaves:

Alternate.
Stipules -
Petiole - yes.
Blade - Egg shaped, 15-40 mm long. Side veins easy to see underneath.

Stems:

Stiff, erect or curving upwards.

Flower head:

Long flower spikes or cluster in axils. Terminal spike long and dense or interrupted.

Flowers:

Bracts - shorter than perianth. Have separate male and female flowers on the same spike.
Ovary - 2 or 3 styles.
Perianth - 2 mm long. 5 segments, narrow spoon shaped with fine point. Erect. Greenish and turning white with age.
Stamens - 3-5.
Anthers -

Fruit:

Remains attached. 2 mm long. Wrinkled with a smooth top with 2-3 styles.

Seeds:

Black. Shiny. Loose within fruit. 1.5 mm wide. Single.

Roots:

Taproot.

Key Characters:

Biology:

Life cycle:

Annual.

Physiology:

Reproduction:

Flowering times:

Seed Biology and Germination:

Vegetative Propagules:

Hybrids:

Allelopathy:

Population Dynamics and Dispersal:

Origin and History:

Australia.

Distribution:

NT, QLD, SA, WA.

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Soil:

Plant Associations:

Significance:

Weed.

Beneficial:

Detrimental:

Toxicity:

Not reported as toxic, but other closely related species may have toxic levels of oxalates and nitrates.

Legislation:

None.

Management and Control:

Thresholds:

Eradication strategies:

Herbicide resistance:

Biological Control:

Related plants:

Boggabri weed (Amaranthus mitchellii)
Dwarf Amaranth (Amaranthus macrocarpus)
Foxtail (Amaranthus paniculatus)
Green Amaranth (Amaranthus viridis)
Love Lies Bleeding (Amaranthus caudatus)
Needleburr (Amaranthus spinosus)
Powell's Amaranth (Amaranthus powellii)
Redroot Amaranth (Amaranthus retroflexus)
Redshank (Amaranthus cruentus)
Rough fruited Amaranth (Amaranthus muricatus)
Slim Amaranth (Amaranthus hybridus)
Spreading Amaranth (Amaranthus deflexus)
South American Amaranth (Amaranthus quitensis)
Tumbleweed (Amaranthus albus) has tiny flowers in the leaf axils.
Amaranthus graecizans.
Batchelor's Buttons (Gomphrena spp.)
Cockscomb (Celosia spp.)

Plants of similar appearance:

References:

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). p330.

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #68.7.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.