larkdaisy

Centratherum punctatum subsp. punctatum
infestation (Photo: Chris Gardiner)
habit growing in a garden (Photo: Sheldon Navie)
habit (Photo: Chris Gardiner)
leaf undersides (Photo: Forest and Kim Starr, USGS)
leaves (Photo: Sheldon Navie)
the older stems may become slightly woody towards the base of the plant (Photo: Forest and Kim Starr, USGS)
close-up of relatively broad leaf with sharply-toothed margins (Photo: Sheldon Navie)
hairy stems, upper leaves, and young flower-head with leafy bracts (Photo: Chris Gardiner)
flower-head with numerous small mauve flowers (Photo: Sheldon Navie)
close-up of flower-head showing tubular florets, each with five spreading lobes (Photo: Sheldon Navie)
mature fruit (Photo: Sheldon Navie)
Herb
Alternate
Simple
Purple
Blue
Green

An upright or sprawling herbaceous plant usually growing 10-50 cm tall. Its alternately arranged leaves (2-8 cm long) have winged stalks and bluntly or sharply toothed margins. Its mauve, purple or blue flower-heads are surrounded by a row of 3-8 large leaf-like bracts. These flower-heads have 30-60 small flowers surrounded by several rows of smaller bracts. Its pale brown 'seeds' (1-2.5 mm long) are topped with a row of narrow bristle-like scales (1-3 mm long).

Common names 
Also known as: larkdaisy, Brazilian bachelor's button, Brazilian button flower, centratherum, lark daisy, porcupine flower,
Family 
Asteraceae
Deciduous 
No
Flowering time 
Year round
Native/Exotic 
Exotic
Origin 
Native to Mexico, Central America, the Caribbean and tropical South America.
Notifiable 
No
Council declaration 
SIL – Special Investigation List
Known distribution 

Naturalised in the coastal districts of south-eastern Queensland (i.e. in the Moreton and Wide Bay districts). Also widely naturalised in other parts of eastern Australia (i.e. the coastal districts of central and northern Queensland and the coastal districts of central and northern New South Wales), but not very common.

Habitat 

A weed of roadsides, riparian vegetation, forest margins, open woodlands, grasslands, pastures, hillsides, parks, lawns, footpaths, gardens, disturbed sites and waste areas.

Habit 

An upright (i.e. erect) or sprawling, short-lived (i.e. annual), herbaceous plant usually growing 10-50 cm tall. Occasionally a small shrubby plant developing a woody base and reaching up to 1 m in height.

Impact and control methods 
Stem and leaves 

The branched stems are slightly ridged (i.e. striate) and sparsely to moderately hairy (i.e. pubescent). The alternately arranged leaves (2-8 cm long and 6-40 mm wide) are simple and borne on winged stalks (i.e. petioles). These leaves are egg-shaped in outline (i.e. ovate or obovate) to somewhat elongated in shaped (i.e. broadly lanceolate) with sharply toothed (i.e. serrate) margins and pointed tips (i.e. acute apices). Their upper surfaces are mostly hairless (i.e. glabrous or puberulent) while their undersides are sparsely to moderately hairy (i.e. puberulent to pubescent).

Flowers and fruits 

The flower-heads (i.e. capitula) are borne singly at the tips of the branches, or occasionally clustered in twos or threes. They are borne on stalks (i.e. peduncles), but may appear to be stalkless as they are surrounded by a row of 3-8 large leaf-like bracts (12-25 mm long). These flower-heads (20-25 mm across at the base) have 30-60 small flowers (i.e. tubular or disc florets) surrounded by several rows of smaller bracts (i.e. an involucre) 5-7 mm long. The tubular florets (9-14 mm long) are mauve, purple or blue in colour with five spreading lobes. Flowering occurs throughout the year, but mainly during summer and autumn. The pale brown 'seeds' (i.e. achenes or cypselae) are cylindrical to club-shaped (i.e. clavate) and ribbed lengthwise. These 'seeds' (1-2.5 mm long) are initially topped with a row of numerous narrow straw-coloured, bristle-like, scales (1-3 mm long).

Reproduction and dispersal 

This species reproduces by seed, which are commonly spread in dumped garden waste and contaminated soil. They may also be dispersed by wind and water.

Similar species 

Larkdaisy (Centratherum punctatum subsp. punctatum) is very similar to the native bubble gum plant (Centratherum australianum). These species can be distinguished from each other by the following differences: larkdaisy (Centratherum punctatum subsp. punctatum) has relatively broad (i.e. obovate or broadly lanceolate) leaves with 10-18 pairs of sharp teeth. Its relatively showy flower-heads are 20-25 mm across at the base bubble gum plant (Centratherum australianum) has relatively narrow (i.e. oblanceolate) leaves with 0-8 pairs of blunt teeth. Its relatively small flower-heads are 8-15 mm across at the base.