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Baccharis glutinosa

Description
 

Chilquilla (Baccharis glutinosa) is a robust herb or sub-shrub to about 1 m high arising from a strong, branching rootstock that is capable of giving rise to new aerial stems. Stems appear to die down annually. The main stem is erect, usually unbranched in the lower half and with only a few erect branches in the upper part. Leaves are mostly 2-8 cm long and 2-8 mm wide, usually widest above the middle. There are usually 3-8 narrow teeth or lobes on either side, but the smaller leaves amongst the flower heads often lack teeth. Stems and leaves lack hairs, but may be covered by a slightly sticky resin.

 

Flowers are borne in cup-shaped heads at the ends of the stems, the heads usually about 5-15 together in loose clusters. Male and female flowers are on separate bushes. Individual flowers (florets) are surrounded by 2 or 3 rows of narrow scale-like bracts (modified leaves) 1-4 mm long. These are hairless, pale green and often reddish- or purple-tipped. There are no ray-florets (the spreading petal-like florets that are characteristic of 'typical' daisies). Old florets develop a tuft of silky hairs (a pappus) to about 4 mm long (Parsons & Cuthbertson 1992; Walsh 2007, pers. comm.).

 

For further information and assistance with identification of Chilquilla contact the herbarium in your state or territory.

Distribution:

Chilquilla is currently known only from an infestation of about 4 ha on private land near Maryborough, Victoria (National Herbarium of Victoria 2007). Future potential spread of the plant is probably confined to relatively moist, warm-temperate to subtropical areas (Cunningham & Brown 2006).

 

It is also a weed of the western part of the United States and in South Africa (Herman et al. 2000).

Habit:Herb, Shrub
Key points:
  • Chilquilla (Baccharis glutinosa) is currently a species of relatively low infestation level over an area of approximately 4 ha.
  • Plants are apparently all female at the site and probably do not produce viable seed.
  • Plants are able to resprout from the rootstock and are thus able to survive significant disruption.
  • Future outbreaks of Chilquilla are likely to be confined to areas near waterways or to seasonally inundated sites.
  • It has the potential to become a weed of irrigated crops in Australia.
How it spreads:

The related groundsel bush (Baccharis halimifolia) spreads by its seeds which are dispersed by wind and water, assisted by the fluffy pappus (Parsons & Cuthbertson 1992). However, because Chilquilla does not appear to produce seed in Victoria, dispersal at this stage appears to be confined to transport of whole plants or fragments of the regenerative rootstock (National Herbarium of Victoria 2007; Walsh 2007, pers. comm.).

 

Where it grows:

In Victoria Chilquilla occurs in pasture and has been recorded in an oat crop (National Herbarium of Victoria 2007). In this area, some plants grow in a shallow drainage channel.

 

In the western states of the United States it has been reported to form dense thickets along borders and banks of moist areas interfering with irrigation (US Army Corps of Engineers 2002). In its native Argentina the species appears to favour riparian sites and adjacent areas prone to seasonal inundation (Perelman et al. 2003).

 

Flower colour:White
Distribution map: See Australia's Virtual Herbarium

http://www.rbg.vic.gov.au/cgi-bin/avhpublic/avh.cgi 

Impacts:

Chilquilla is one of seventeen sleeper weeds identified by the Bureau of Rural Sciences (following consultation with the Australian Weeds Committee) which could have nationally significant impacts on agriculture if allowed to spread.

 

Currently the impact of Chilquilla is relatively slight, reducing somewhat the capacity of the Victorian site to carry stock and/or produce cereal grain. Like other Baccharis spp. it could become persistent weeds in flood plains, old fields, or similar habitats (Cunningham & Brown 2006). It is a weed of irrigated crops overseas and climatically suited to irrigation regions in Australia (Cunningham et al. 2006).

 

Origin:

Chilquilla is native to Chile, Argentina and Brazil (Zdero et al. 1990).

 

History:Chilquilla was first reported in Victoria in 1988 (National Herbarium of Victoria 2007), but was known at the site for several years before that time. It is likely to have originated as a contaminant in a pasture or crop seedlot originating from South America, the United States or South Africa (Walsh 2007, pers. comm.).

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This database is designed to provide information, including biological and ecological, on invasive plant species that are on a national weed list, or are legislated against in a state or territory. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. For further information on the images contained in the database please contact the copyright owner. All images in the weed identification tool are managed by the Australian Plant Image Index (APII). Various copyright conditions apply for these images. For further information on the copyright conditions of images contained in the database please contact the APII at: photo@anbg.gov.au.