Centratherum punctatum Cass. subsp. punctatum
Centratherum punctatum Cass.
Asteraceae
Brazilian bachelor's button, Brazilian button flower, centratherum, lark daisy, larkdaisy, porcupine flower
Native to Mexico, Central America, the Caribbean and tropical South America.
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.
A weed of roadsides, riparian vegetation, forest margins, open woodlands, grasslands, pastures, hillsides, parks, lawns, footpaths, gardens, disturbed sites and waste areas.
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.
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).
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).
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.
This species is not declared under any state or local government legislation in the region.
As this species is not a declared plant, its control is not required and there are no restrictions on its sale or cultivation. However, it is a minor environmental weed and should be managed in sensitive bushland and conservation areas.
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 spread from cultivation as a garden ornamental, and occasionally become naturalised in native vegetation (e.g. in open woodlands and riparian vegetation) and disturbed sites in south-eastern Queensland. It is a minor environmental weed in the region.