Description
African Rue (Peganum harmala) is an erect, stiff-stemmed perennial herb or shrubby plant growing from 30 to 80 cm high. The stems are hairless and slender, much branched, and arise from short, long-lived underground stems. The leaves are alternately arranged, 2-5 cm long, somewhat succulent, bright green in colour, and are deeply divided into three or more narrow linear segments. The flowers are solitary, about 2.5 cm across, and borne on slender stalks up to 5 cm long. The flowers have 5 broad white petals (12-17 mm long), surrounded by 5 narrow green sepals (8-20 mm long). The fruits are rounded but flattened capsules, 8-12 mm across and 7-12 mm long, are 3-celled, and contain numerous black, angular seeds (Eichler 1986; Parsons & Cuthbertson 2001; Navie 2004).
For further information and assistance with identification of African Rue contact the herbarium in your state or territory.
Distribution:
African Rue is mainly confined to south-eastern areas of South Australia, but occurs occasionally in southern New South Wales and northern Victoria (Navie 2004). In South Australia it occurs in isolated patches in the Flinders Ranges, Northern Lofty, Eastern, Murray, and South-eastern regions (Eichler 1986).
Habit:
Herb
Key points:
- African Rue (Peganum harmala) is a shrubby perennial species occurring in temperate, semi-arid and arid regions, predominantly in south-eastern South Australia.
- It is drought and salt tolerant.
- Its effect on native species is unassessed, but it could potentially impact significantly on native plant communities is semi-arid environments.
- Although toxic, it appears to be highly unpalatable to stock.
How it spreads:
Dispersal of African Rue is mainly by seeds, the majority of which fall close to the parent plant. Seeds can be dispersed by the flow of water over the soil surface, in mud tracked by animals or vehicles, or by animals/stock which may eat the fruit (Parsons & Cuthbertson 2001). Asexual reproduction can occur by suckering from the root system, and the plant can therefore be dispersed if rootstock is moved to new areas during cultivation (Parsons & Cuthbertson 2001; Navie 2004).
Where it grows:
African Rue occurs in temperate, sub-tropical, semi-arid and arid areas to altitudes of up to 2500 meters (Parsons & Cuthbertson 2001). As a weed it occurs most frequently in dryer areas, growing on waste areas, roadsides, cultivated areas, and pastures. It also inhabits rangelands and grasslands (Navie 2004).
Flower colour:
White
Impacts:
African Rue can be toxic due to the presence of several alkaloids occurring in all parts of the plant. However, the plant appears to be highly unpalatable to stock due to its bitter taste, and there are few actual reports of poisonings (Parsons & Cuthbertson 2001).
Although it is a vigorously growing plant, it only occurs sporadically in small patches throughout parts of South Australia, and only occasionally in New South Wales and Victoria. Its effect on native plant communities is unassessed, but it is somewhat drought and salt tolerant, and could cause considerable problems in semi-arid and arid regions (Parsons & Cuthbertson 2001).
Origin:
African Rue is native to Spain and from northern Africa across to Tibet (Richardson et al. 2006), and extends into areas in Pakistan, India and southern Russia (Parsons & Cuthbertson 2001; USDA 2007).
History:
The precise time of introduction of African Rue into Australia is not known. It was introduced into the United States in 1928, and probably later into Australia (Parsons & Cuthbertson 2001). It was recorded as naturalised in New South Wales on heavy soils at Wirruna Station in 1933 and at Savernake in 1937, but is currently most common in South Australia (Parsons & Cuthbertson 2001; Navie 2004).
