Form: herbaceous — annual or short-lived perennial
Status: present in WA
Appearance
Senna obtusifolia is a vigorous annual or short lived perennial native of tropical America that grows to a height of 2.5 metres. Non-nodulating. Similar to Senna tora except for presence of a single gland at the rachis of the lower pair of leaflets. Also the petals and the flower stalk are longer in this species.
Stems: Numerous branching to a height of 1.5-2 metres height, usually slightly hairy.
Leaves: Alternate, divided into two to three pairs of opposite leaflets with rounded tips, two to three centimetres long, 1.5-2 centimetres wide, wedge-shaped at base; a single elongated gland occur on the stalk between the lowest pair of leaflets.
Flowers: Yellow 1-1.5 centimetres diameter, with five petals. Usually in pairs at the base of the uppermost leaves.
Fruit: Brownish green, slender compressed pod 10-15 centimetres long, 3-5 millimetres wide, sickle shaped and slightly indented between the seeds.
Seeds remain viable for many years. Serious invader of crops and pasture land in wet tropics. Rarely eaten by stock.
Agricultural and economic impact
An environmental weed. Senna obtusifolia and S. tora are highly economically detrimental to a number of agricultural crops especially in North America and Australasia. S. obtusifolia is spreading and displacing native vegetation in the Australasia/Pacific regions. In places it produces impenetrable monotypic stands. In Australia it is thought to increase the risk of damage to forest by fire.
Declared pest category
The Western Australian Organism List (WAOL) contains information on the area(s) in which this pest is declared and the control and keeping categories to which it has been assigned in Western Australia (WA). Search for sicklepod (Senna obtusifolia) in theWAOL using the scientific name Senna obtusifolia.
Requirements for land owners/occupiers and other persons
Requirements for land owners/occupiers and other persons if this pest is found can be sourced through the declared plant requirements link.
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Control method
Control methods for this declared plant can be found through the sicklepod (Senna obtusifolia) control link.