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Electronic Flora of South Australia
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Electronic Flora of South Australia species Fact Sheet

Family: Asteraceae
Ambrosia psilostachya

Citation: DC., Prod. 5:526 (1836).

Synonymy: A. artemisiifolia sensu J. Black, Fl. S. Aust. 602 (1929), non L.

Common name: Perennial ragweed, western ragweed.

Stoloniferous perennial to 2 m high, forming dense colonies; stems erect, simple or branched in the upper portion, striate, scabrous; woody at the base; leaves broadly lanceolate, shortly petiolate, 5-12 cm long, pinnatipartite with lanceolate often toothed segments 2-4 mm wide, green, pubescent with appressed hairs.

Racemes several, erect, terminating branches at the top of the plant, 3-12 cm long; male capitula numerous, c. 3 mm diam., on pedicels c. 1 mm long; florets numerous, not exceeding the involucre, a pale greenish-yellow; female capitula solitary, rarely paired, in axils.

Fruiting capitula turbinate, 3-4 mm long, reticulate, 5-ribbed, with 5 short spines above and a longer central beak at the apex.

image of FSA3_Ambrosia_psi.jpg Twig, male and female capitula and portion of leaf.
Image source: fig. 642a in Jessop J.P. & Toelken H.R. (Ed.) 1986. Flora of South Australia (4th edn).

Published illustration: Parsons (1973) Noxious weeds of Victoria, p. 88).

Distribution:  Weed of waste ground, roadsides, stream banks and irrigated land.

S.Aust.: MU, SL.   W.Aust.; N.S.W.; Vic.

Conservation status: naturalised

Flowering time: most of the year.

SA Distribution Map based
on current data relating to
specimens held in the
State Herbarium of South Australia

Biology: No text

Author: Not yet available

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