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Scientific Name
Family
Common Names
Origin
Naturalised Distribution
Habitat
Habit
Distinguishing Features
Stems and Leaves
Flowers and Fruit
Reproduction and Dispersal
Environmental Impact
Legislation
Management
Similar Species
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Click on images to enlarge

large infestation (Photo: Forest and Kim Starr, USGS)

habit (Photo: Sheldon Navie)

habit (Photo: Sheldon Navie)

toothed lower leaves, which are occasionally also three-lobed (Photo: Sheldon Navie)

toothed upper leaves (Photo: Sheldon Navie)

close-up of stem with clasping leaf bases (Photo: Sheldon Navie)

young flower-heads (Photo: Sheldon Navie)

close-up of one of the daisy-like flower-heads (Photo: Sheldon Navie)

close-up of the underside of a flower-head, showing the floral bracts (Photo: Sheldon Navie)

young plant (Photo: Sheldon Navie)

yellow flower-heads with several 'petals' (Photo: Sheldon Navie)

close-up of 'seeds' topped with fluffy hairs (Photo: Sheldon Navie)

Senecio madagascariensis

Scientific Name

Senecio madagascariensis Poir.

Family

Asteraceae (Queensland, New South Wales, the ACT, Victoria, Tasmania, Western Australia and the Northern Territory)
Compositae (South Australia)

Common Names

fire weed, fireweed, Madagascar ragwort

Origin

Native to southern Africa (i.e. South Africa and Swaziland) and Madagascar.

Naturalised Distribution

Widely naturalised in eastern Australia (i.e. in south-eastern Queensland and eastern New South Wales). Also present in inland southern New South Wales, sparingly naturalised in the ACT and near Melbourne in southern Victoria, and recently found in northern Queensland.

Also naturalised overseas in Hawaii.

Habitat

A weed of pastures, open woodlands, grasslands, suburban bushland, roadsides, disturbed sites, waste areas, parks and coastal environs in sub-tropical and and warmer temperate regions.

Habit

An upright (i.e. erect or ascending) and relatively short-lived herbaceous plant (i.e. it may be annual, biennial or perennial) usually growing 10-50 cm tall, but occasionally reaching up to 70 cm in height.

Distinguishing Features

Stems and Leaves

Plants can have a single main stem, or several stems that develop from a central crown at the base of the plant. These stems are much-branched towards the top of the plant and bear large numbers of flower-heads at their tips.

The alternately arranged and simple leaves (2-12 cm long and 3-25 mm wide) are variable in shape, though they are usually quite narrow and elongated (i.e. lanceolate). Leaf margins are usually toothed (i.e. denticulate to coarsely serrated), but may sometimes be entire or even lobed (i.e. pinnatifid). These leaves are all stalkless (i.e. sessile) and generally have a broad base which tends to clasp around the stem. Stems and leaves are hairless (i.e. glabrous) or sparsely hairy (i.e. puberulent).

Flowers and Fruit

The 'daisy-like' flower-heads (15-20 mm across) have 12-15 yellow 'petals' (i.e. ray florets) that are 6-14 mm long. They have a yellow centre made up of numerous tiny flowers (i.e. tubular or disc florets) and are surrounded by about twenty (19-21) greenish bracts (4-5 mm long). These flower-heads (i.e. capitula) are loosely clustered at the tips of the branches. Flowering usually occurs from late autumn through to the middle of summer, but some plants may continue to flower until late summer if conditions are favourable.

Seeds (i.e. achenes) are cylindrical in shape (1.5-3 mm long and less than 0.5 mm wide), brownish in colour and shallowly ribbed. They are covered with very tiny hairs and topped with a silky tuft (i.e. pappus) of hairs (3.5-6.5 mm long).

Reproduction and Dispersal

This plant reproduces by seed, and occasionally via crown segments.

Most dispersal of seed is by wind movement, but some seeds may be spread by animals, vehicles and in contaminated agricultural produce.

Environmental Impact

Fireweed (Senecio madagascariensis) is regarded as an environmental weed in Queensland and New South Wales. It was also recently listed as a priority environmental weed in four Natural Resource Management regions.

Legislation

This species is declared under legislation in the following states and territories:

Management

For information on the management of this species see the following resources:

Similar Species

Fireweed (Senecio madagascariensis) is very similar to several native and introduced species, including variable groundsel (Senecio pinnatifolius ), ragwort (Senecio jacobaea), African daisy (Senecio pterophorus) and Dalton weed (Senecio daltonii). These species can be differentiated by the following differences: