African Rue

Peganum harmala L.

Family: Zygophyllaceae.

Names:

Peganum is from the Greek peganon the name for rue, a herb used for medicine and seasoning, which this plant is supposed to resemble.
Harmala is derived from the Arabic name for this plant, harmal.
African Rue indicates an African form of the plant. Rue is the herbalists' name for a perennial with bitter, scented leaves used for medicinal purposes.

Other names:

Aspand
Esfand
Harmal (Pakistan)
Harmel (California)
Isband (Hindi)

Summary:

A bushy, summer growing rhizomatous shrub with fleshy divided leaves, stiff branches, single, white flowers and an orange globular fruit.

Description:

Cotyledons:

Two.

Leaves:

Alternate.
Stipules - Bristle like.
Petiole -
Blade - 20-50 mm long, divided into 3 segments that may be divided again into narrow parallel sided spreading segments, bright green, fleshy.

Stems:

300-800 mm high, slender, rigid, many branched, circular near the base, angled near the top. Hairless. Arising from short, underground, perennial rhizomes.

Flower head:

Single flowers on stalks (peduncles) from leaf axils. Peduncles longer than leaves.

Flowers:

White. 25 mm diameter. Bisexual.
Ovary - Globular, Style stigmatic on back. Many ovules
Sepals - 5, overlapping, green, parallel sided, narrow, 15 mm long, about as long as the petals.
Petals - 5, egg shaped to oblong, overlapping, 15 mm long, white.
Stamens - 12-15 inserted at the base of a short disk.
Anthers -

Fruit:

3 celled, globular capsule, 7-12 mm long x 12 mm diameter. Opens along the top and back of the cells in 3 valves to release seed. Many seeds in each cell.

Seeds:

Angular, Black, Spongy seed coat.

Roots:

Underground perennial rhizome. Branching taproot with a thick rootstock. Laterals mainly 150 mm or more deep.

Key Characters:

White, 5 petalled, single flowers. Much divided leaves. Hairless stems that are round at the base and angular at the top. Globular, orange, 3 celled fruit.

Biology:

Life cycle:

Perennial. Seed germinates in spring and to a lesser extent in summer. Seedlings grow slowly. Flowering starts in late spring and continues until April with peaks in November/December and March. Fruit ripens 4 weeks after flowering. All top growth dies off in winter and the plant sprouts again in August/September.

Physiology:

Salt tolerant.
Very drought tolerant.
Growth rates of 2-3 mm/day have been recorded in pots.

Reproduction:

By seed.

Flowering times:

Summer in SA.

Seed Biology and Germination:

Germinates in day/night temperatures of 36/21oC.
Germinates from 30 mm deep with an optimum depth of 5 mm.

Vegetative Propagules:

Rootstock that regenerates when damaged.

Hybrids:

Allelopathy:

Population Dynamics and Dispersal:

Seed is spread by flowing water and in mud carried by stock or machinery. Some may be spread by stock eating seeds and passing them in droppings. Pieces of rootstock moved by cultivation can form new plants.

Origin and History:

Mediterranean. North Africa. Southern USSR. Tibet. Spain. India.
Introduced to Australia about 1930.

Distribution:

NSW, SA.

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Temperate and sub-tropical steppe, semi-desert and desert areas to altitudes of 2500 m.

Soil:

Most abundant on heavy soils.

Plant Associations:

Significance:

Beneficial:

Used as a spice.
Used as a herbal medicine as an aphrodisiac, abortifacient and for the treatment of asthma, neuralgia, rheumatism, jaundice, colic, diuretic and anthelmintic for tapeworms.
The seed contains an edible oil.

Detrimental:

Weed of roadsides, pastures and areas receiving supplemental water.
Unpalatable to stock.

Toxicity:

Contains toxic alkaloids in all plant parts.
Toxic when green but seldom causes poisoning.
The seed coat and young leaves are most toxic.

Symptoms:

Paralysis of the hindquarters and weakness of the back muscles occurs within an hour of feeding and lasts several hours.

Treatment:

Remove stock from infested area

Legislation:

Noxious weed of SA and WA.

Management and Control:

Mechanical removal is difficult because of re-shooting from severed roots. Mowing and slashing are ineffective. Isolated plants can be spot sprayed with glyphosate just before flowering. Bromacil, diuron, tebuthiuron and imazapyr provide good control in various situations.

Thresholds:

Eradication strategies:

Prevent seed set by spraying before flowering.
Cultivate a few weeks after spraying.
Spray regenerating root fragments and seedlings.

Herbicide resistance:

Biological Control:

Related plants:

None.
It is in the same family as Caltrop (Tribulus terrestris).

Plants of similar appearance:

References:

A.P.B. Infonote 10/87 (1987)

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P491 535.

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney). P761.

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). #942.1.

Parsons, W.T. and Cuthbertson, E.G. (1992). Noxious weeds of Australia. (Inkata Press, Melbourne). P637-639. Photos.

Acknowledgments:

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