Plants of South Eastern New South Wales
Ambrosia psilostachya
Common name
Perennial Ragweed
Family
Asteraceae
Where found
Pastures, roadsides, wasteland, and along streams. Sydney area to Gosford.
Notes
Introduced perennial herb to 2 m high, stoloniferous, often forming dense colonies. Stems grooved, hairy to rough, woody at the base. Leaves alternating up the stems, aromatic when rubbed, mostly 4–12 cm long, 20–40 mm wide, rough to hairy, divided into several pointed lobes. Male and female flowers on the same plant. Male heads cream to greenish yellow or greenish, small, hemispherical, 2-3 mm in diameter, in branching spike-like flower clusters. Female heads with 1 tiny floret, in clusters of 2-7 flower heads. Flowering: spring–summer.
General Biosecurity Duty all NSW. Noxious weed Vic.
PlantNET description: http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Ambrosia~psilostachya (accessed 3 January, 2021)
The description above partly based on the description in Weeds in Australia http://www.environment.gov.au/cgi-bin/biodiversity/invasive/weeds/weeddetails.pl?taxon_id=7772 (accessed 3 January, 2021)
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