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

Family: Compositae
Senecio jacobaea

Citation: L., Sp. Pl. 2:870 (1753).

Synonymy: Not Applicable

Common name: Ragwort.

Biennial subshrub, with a short thick rootstock, sparsely to densely cottony, glabrescent on the oldest parts; stem erect, stout, striate, often purplish-red, branching above the middle; basal leaves petiolate, lyrate, to 20 cm long, withering early; mid-stem leaves oblong-ovate, 8-15 x 3-4 cm, pinnatisect, the lobes irregularly toothed or lobed, sessile, stem-clasping.

Inflorescence a congested corymbose panicle of numerous capitula; involucre campanulate, 4-5 x 3.5-4 mm, bracts 11-13, abruptly narrowed c. 1 mm below the ciliolate apices; calyculus of 3-5 finely tapered bracteoles; ray florets 10-15; ligules of small heads c. 4 x 1.5 mm, of larger heads 6-10 x 1-1.8 mm; disk florets c. 40.

Achenes 1.8-2 mm long, plump, brown, those of the ray florets glabrous, those of the disk florets with short appressed hairs; pappus uniform, deciduous.

Published illustration: Lamp & Collett (1976) Field guide to weeds in Australia, p. 284.

Distribution:  Occurs in pasturages, along roadsides, and in dry sclerophyll woodlands.

S.Aust.: SL.   Vic.; Tas.   New Zealand, United States (California); native of Europe, widely adventive.

Conservation status: native

Flowering time: Dec. — May.

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

Biology: No text

Taxonomic notes: Apparently first collected in South Australia in 1954, but present in Tasmania as early as 1919 and widespread over much of the island. A noxious weed poisonous to livestock by cumulative liver damage.

Author: Not yet available

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