Common name: Fireweed Groundsel, Fireweed
Senecio linearifolius A.Rich. APNI* 
Description: Perennial herb or shrub 50–150 cm high, stems few-branched, glabrous to cobwebby.
Leaves variable, mostly linear to lanceolate or narrow-elliptic, 6–15 cm long and 5–15 mm wide with margins ± recurved and entire to sparsely toothed, lower surface mostly cobwebby, base tapered and petiole-like; or sometimes leaves ± elliptic to obovate, 5–10 cm long and 10–30 mm wide with margins strongly and regularly toothed, lower surface glabrous, lamina scarcely tapered and base stem-clasping and auriculate.
Inflorescence corymbose, heads numerous; heads cylindrical, 2–3 mm diam., glabrous except at apices; involucral bracts 10–12, 4–5 mm long; bracteoles c. 5. Ray florets 4–8; ligules 4–6 mm long; disc florets 8–12.
Achenes compressed, 2–2.5 mm long, brown, glabrous; pappus 5–8 mm long.
Flowering: throughout year.
Distribution and occurrence: Chiefly in the escarpment ranges, south from Tenterfield and west to Nundle. Mostly in wet sclerophyll forest.
NSW subdivisions: NC, CC, SC, NT, CT, ST, NWS, SWS
Other Australian states: Vic. Tas.
Text by G. J. Harden
Taxon concept: Flora of NSW 3 (1992)
| | Key to the varieties | |
| 1 | Plants never glaucous | 2 |
| Plants slightly to moderately or strongly glaucous | 4 |
| 2 | Young leaves densely woolly, lower surface remaining slightly to moderately obscured by wispy hairs; achenes usually glabrous | var. arachnoideus |
| Young leaves not woolly; lower surface of mature leaves glabrous or somewhat cobwebby
Back to 1 | 3 |
| 3 | Leaves to 20 mm wide; leaves on upper stem with l:b ratio of 4–15 (sea-level to montane) | var. denticulatus |
| Leaves to 50 mm wide; leaves on upper stem with l:b ratio of 1.5–6 cm (montane to alpine)
Back to 2 | var. latifolius |
| 4 | Leaves on upper stem with l:b ratio of up to 30 (tablelands) | var. intermedius |
| Leaves on upper stem with l:b ratio of 5–8
Back to 1 | 5 |
| 5 | Leaves lacking hairs on lower surface, mildly glaucous (rarely not glaucous); achenes glabrous | var. macrodontus |
| Leaves usually with some hairs on lower surface, strongly glaucous; achenes with papillose hairs
Back to 4 | var. dangarensis |
APNI* Provides a link to the Australian Plant Name Index (hosted by the Australian National Botanic Gardens) for comprehensive bibliographic data
***The AVH map option provides a detailed interactive Australia wide distribution map drawn from collections held by all major Australian herbaria participating in the Australian Virtual Herbarium project.
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