cobbler's pegs
"A short-lived herbaceous plant with upright stems growing up to 1.8 m tall. Its stems are square in cross section and green to purplish in colour. Its paired leaves (2.5-13.5 cm long) have toothed margins and vary in nature depending on their position on the plant. They may be either oval in shape, deeply-lobed or once-compound with 3-7 leaflets. Its small flower-heads (5-15 mm across) have numerous tiny yellow tubular flowers in the centre and sometimes also have some white ‘petals’ 2-8 mm long. Its dark brown or black 'seeds' (4-16 mm long) are elongated in shape and topped with two or three barbed awns (1-4 mm long).
A widely naturalised species that is particularly common in the eastern and northern parts of Australia.
This species is a common weed of crops, fallows, orchards, vineyards, waste areas, disturbed sites and populated areas (e.g. gardens, footpaths, parks, etc.). It is also found in re-vegetation areas, forest gaps and margins, open woodlands, urban bushland, riparian vegetation and coastal enviorns.
A short-lived (i.e. annual) herbaceous plant with upright (i.e. erect) stems usually growing 0.3-1 m tall, but occasionally reaching up to 1.8 m in height.
"This very common weed grows in a wide variety of habitats. Cobbler's pegs (Bidens pilosa) is well known as a weed of gardens, parks, crops, pastures, roadsides, disturbed sites and waste areas, but it also invades waterways, rainforest margins, open woodlands and coastal sites. For this reason it is also regarded as an environmental weed in New South Wales and Queensland.
Cobbler's pegs (Bidens pilosa) is considered to be among the 200 most invasive plant species in south-eastern Queensland. Dense populations can out-compete native species, and are particularly troublesome in revegetation sites and on the exposed margins of bushland."
"The stems are square in cross section (i.e. quadrangular), mostly hairless (i.e. glabrous) or hairy (i.e. pubescent), and green to purplish in colour.
The paired leaves (2.5-13.5 cm long and 2-11 cm wide) are borne on slightly winged stalks (i.e. petioles) 1-7 cm long, and vary in nature depending on their position on the plant. At the base of the plant the leaves tend to be simple and more or less oval (i.e. elliptic) in shape. Along the stems they are either deeply lobed (i.e. pinnatisect), with three to seven lobes, or once-compound (i.e. pinnate) with 3-7 leaflets that are egg-shaped in outline (i.e. ovate). The uppermost leaves are either simple or have three leaflets, and are usually smaller and narrower (i.e. lanceolate). The leaves, or leaflets, have sharply-toothed (i.e. serrate) margins and pointed tips (i.e. acute apices). Leaves or leaflets also vary somewhat in size depending on their location on the plant (i.e. they are from 1.5-12 cm long and from 0.5-8 cm wide). They are either hairless (i.e. glabrous) or sparsely hairy (i.e. puberulent)."
"The small flower-heads (i.e. capitula) are borne singly, but are often arranged in loosely branched clusters at the tips of the stems. These flower-heads (5-15 mm across) are borne on stalks (i.e. peduncles) 1-9 cm long have numerous small yellow tubular flowers (i.e. tubular or disc florets) 3-5 mm long in the centre. They sometimes also have one to several white ‘petals’ (i.e. ray florets) 2-8 mm long and are enclosed in two rows of bracts (i.e. involucral bracts). The outer row of bracts (2.7-5 mm long and 0.5-1.2 mm wide) are green with finely hairy (i.e. ciliate) margins, while the inner row of bracts (3-5 mm long and 1-1.8 mm wide) are brownish in colour with pale margins. Flowering occurs throughout most of the year.
The 'seeds' (i.e. achenes or cypselae) are dark brown or black in colour, flattened, and elongated (i.e. linear) in shape. These 'seeds' (4-16 mm long) have a few ridges with tiny hairs (i.e. they are antrorsely hispidulous) and are topped with two or three barbed awns (1-4 mm long)."
This species reproduces only by seed, which readily become attached clothing and animals. The seeds may also be dispersed by vehicles, by water, and in contaminated agricultural produce.
"Cobbler's pegs (Bidens pilosa) is very similar to beggar's-ticks (Bidens alba var. radiata) and greater beggar's-ticks (Bidens subalternans) and bipinnate beggar's-ticks (Bidens bipinnata). These species can be distinguished by the following differences:
■cobbler's pegs (Bidens pilosa) has flower-heads without any 'petals' (i.e. ray florets) or has several small white 'petals' 2-8 mm long. Its leaflets are toothed, but are not usually further divided, and its 'seeds' (i.e. achenes) are topped with two or three upright or spreading (i.e. erect or divergent) awns.
■beggar's-ticks (Bidens alba var. radiata) has flower-heads several relatively large white 'petals' (i.e. ray florets) 10-16 mm long. Its leaflets are toothed, but are not usually further divided, and its 'seeds' (i.e. achenes) are topped with two upright or spreading (i.e. erect or divergent) awns.
■greater beggar's-ticks (Bidens subalternans) has flower-heads with several small yellow 'petals' (i.e. ray florets) or has several small yellow 'petals' 5-6 mm long. Its leaflets are usually further divided (i.e. pinnatifid) and its 'seeds' (i.e. achenes) are topped with two or three upright (i.e. erect) awns.
■bipinnate beggar's-ticks (Bidens bipinnata) has flower-heads without any 'petals' (i.e. ray florets) or has several small yellow 'petals' 1-4.5 mm long. Its leaflets are usually greatly divided (i.e. pinnatifid) and its 'seeds' (i.e. achenes) are topped with two or three spreading (i.e. divergent) awns.
Cobbler's pegs (Bidens pilosa) is also relatively similar to native cobbler's pegs (Glossogyne tenuifolia), which has leaves with several very narrow (i.e. linear) segments and flower-heads with small yellow 'petals' (i.e ray florets) 2-4 mm long."
