New Zealand Spinach Tetragonia tetragonoides (Pallas) Kuntze
Synonyms - Tetragonia expansa
Family: - Aizoaceae
Names:
Tetragonia refers to the 4 angled fruit. Tetra is Greek for four and gonia means angle.
New Zealand Spinach. New Zealand refers to its country of origin and Spinach refers to its taste and its use as a cooked vegetable by early settlers.
Other Names:
Native spinach is sometimes used because it is regarded as a native plant in states (and other countries) bordering on the Pacific Ocean.
Botany Bay greens was used after Sir Joseph Banks introduced it to the English in 1772.
Warrigal cabbage.
Summary
A succulent, prostrate annual or short lived perennial with 50-100 mm long leaves and green flowers in the leaf axils. It is often 1 metre diameter and 250 mm tall.
Description
Cotyledons:
Two.
Leaves:
Alternate, succulent, thick, pale green, with small glistening watery blisters.
Stipules - None
Petiole - 4-8 mm long.
Blade - Spear to egg shaped or triangular to rhomboidal, 20-100 mm long by 13-50 mm wide, tapering to the petiole. Tip pointed. Sides convex and undulating. Base tapered. Surface undulating with tiny nipple like warts.
Stems:
Prostrate, running, thick and succulent when young and becoming woody with age, up to 1 m. Young growth sometimes hairy or scaly.
Flower head:
Flowers usually single or in pairs in leaf axils.
Flowers:
Greenish, in leaf axils, on 4-8 mm or smaller stalk.
Ovary - Inferior or half inferior. 1 pendulous ovule in each cell.
Style - 5-11.
Perianth - Greenish, tubular with 4 lobes about 2 mm long. Variable in size shape and hairiness. Fused to the ovary.
Stamens - 8-20. Free. Inserted at the top of the perianth tube. Distributed evenly or in loose groups
Anthers -
Fruit:
Green and succulent and becoming hard, woody, dry, pale brown and angular at base. 5-15 mm long and wide. Usually 3-8 ribs projected into prominent horns at the top that may be equal or unequal. Indehiscent. Very variable, even on the same plant.
Seeds:
Many, pale brown, pear to kidney shaped.
Roots:
Taproot.
Key Characters:
Green flowers.
Flowers subsessile or on short stalks and single or in pairs.
Flower bud without distinct ridges; ridges developing and extending above the ovary in the fruiting stage.
Ovary rounded, not projecting
Styles 3-many
8-many stamens
Angular, dry, hard, sub globular fruits with several horns and no wings.
Adapted from J. Black, G. Harden and N. Marchant.
Biology
Life cycle:
Annual or short lived perennial. Germinates in winter, flowers in spring and summer then most plants die. Some may grow for a year or two.
Physiology:
Drought tolerant.
Reproduction:
Flowering times:
September - January and occasionally July.
Seed Biology and Germination:
Vegetative Propagules:
Hybrids:
Population Dynamics:
Very common following good winter rains in eastern Australia.
Origin and History:
Australia, New Zealand and the Pacific region.
Distribution:
ACT, NSW, NT, QLD, SA, TAS, VIC, WA.
Habitats:
Climate:
Sea coasts to semi desert.
Soil:
Wide range from sands to heavy clays.
Plant Associations:
Found with most vegetation types.
Often found with Purslane (Portulaca oleracea).
Occurs in Brigalow country.
Prevalent on loams carrying bladder saltbush and black bluebush.
Significance:
Beneficial:
Cooked vegetable, used by settlers and cultivated.
Fodder - Opinions vary from rarely eaten to readily eaten and providing valuable moisture for stock. Dried plants are also eaten.
Detrimental:
May have toxic levels of soluble oxalate and occasionally nitrate. However it is rarely eaten by stock and no field cases of poisoning have been reported in Australia.
Weed of crops and pastures.
Serious weed of southern Queensland in wheat and brigalow areas.
Toxicity:
Contains saponins, alkaloids, oxalates (14-16 % by dry weight have been recorded) and occasionally accumulates nitrate. Higher levels of oxalates and nitrates are usually in young plants.
Sheep and cattle are affected.
May cause urinary calculi in wethers.
Under normal grazing situations it would appear that it causes no more than varying degrees of scouring.
Symptoms:
Listlessness, staggering, shortage of breath and sometimes scouring. Usually occurs after unaccustomed stock graze the plant heavily.
Treatment
Don't stress, muster or yard stock. Remove stock from infested areas quietly.
Cattle - Venal injection of 60-180 g calcium borogluconate in 300-900 mL water. Supplement with 1-5 L of lime water or up to 50 g chalk in water or 250-500 g Epsom salts by mouth.
Sheep - Venal injection of 6-20 g calcium borogluconate in 30-100 mL water. Supplement with 0.25-1 L of lime water or 2-5 g chalk in water or 60-100 g Epsom salts by mouth.
If blood is chocolate coloured treat for nitrate poisoning.
Legislation:
None.
Management and Control:
A number of herbicides in the hormone and picolinic acid group are used for control.
Thresholds:
Eradication strategies:
Eradication is inappropriate as this is an Australian native plant.
Herbicide resistance:
None reported.
Biological Control:
Related plants:
Native Spinach (Tetragonia eremacea)
Sea Spinach (Tetragonia decumbens) has yellow flowers rather than green.
Tetragonia fruticosa
Tetragonia nigrescans
Plants of similar appearance:
Canary Creeper (Senecio tamoides)
Iceplant (Mesembryanthemum crystallinum).
References:
Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P66. Photo.
Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P340. Diagram.
Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P296. Photo.
Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney). P690-691.
Harden, Gwen J. (1991). Flora of NSW. (Royal Botanic Gardens, Sydney). Volume 1. P194. Diagram.
Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne). P252. Photo.
Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #1196.5.
Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P79.