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Senecio: From the Latin senex 'old man' (probably referring to the bearded seeds)
cotton fireweed, white fireweed, pahokoraka
Current Threat Status
2012 - Not Threatened
Previous Threat Status
2009 - Not Threatened
2004 - Not Threatened
Senecio quadridentatus Labill.
Vascular - Native
Erechtites quadridentata (Labill.) DC.
Indigenous. Three Kings, North, South, Stewart and Chatham Islands. Present in Australia
Throughout from coastal to subalpine habitats. Always in recently distrubed ground
Short-lived, usually much branched, perennial herb up to 1 m tall. Stems erect, moderately to densely covered in appressed-cottony hairs. Mid stem leaves more or less evenly spaced and sized., linear to narrow linear, 80-220 mm long, length:width ratio (l:w) 15-40 (or 7-10 if lobes present), mostly entire, rarely dissected or lobed, sometimes coarsely dentate to lobate; segments remote 1-3 per side and mainly in proximal half, spreading, triangular, base attenuate or occasionaly with small entire auricles, not amplexicaul; margin entire or with frequentminute denticulations, appearing entire due to revolute margin; upper surface hairs appressed-cobwebby becoming glabrescent; lower surface green or purple-green, moderately to densely woolly. Upper stem leaves similar; auricles more frequent. Unit Inflorescence usually of many capitula; total number of capitula per stem often 50-200; overtopping variable; mature lateral peduncles mostly 5-25 mm long. Calycular bracteoles of capitula 4-8, 1.0-3.0 mm long peduncle and margin of bracteoles cobwebby to woolly at anthesis, or glabrate; involucre 6.0-10.0 x 1.2-2.0 mm; involucral bracts 8-14, basally cobwebby or glabrate, with apex erect; stereomes (in dried material) more or less flat, green or partially purple, sometimes minutely black-tipped or purple in a zone 1 mm long below tip. Florets 18-50, c. 80% female; corolla-lobes triangular, not or hardly thickened apically; corolla of bisexual florets 6-9 mm long, 4-lobed; corolla-lobes of female florets 3, 0.1 mm long. Cypsela 2.2-3.5 mm long, subcylindric, narrow to and constricted below apex, usually with 2-3 rows of hairs in narrow grooves between broad ribs, sometimes glabrous.
Seencio dunedinensis Belcher is similar and could be confused. Generally it is a smaller less heavily branched plant, with much wider dark green to purple-green glabrescent leaves. The involucral bracts are 4-6 mm rather than 6-10 mm long. Senecio quadridentatus tends to grow at lower altitudes than S. dunedinensis but at times the two species are sympatric and some of the variation seen between both species may be due to hybridism.
October - March
Main Flower Colour
Other Flower Colour
December - May
Easy from fresh seed. The silvery white foliage can be quite attractive but this species is invasive. Prefers full sun.
2n = 40
Where To Buy
Not commercially available.
Unpublished Molecular evidence (nrDNA ITS sequences) held by University of Auckland place this species as sister to S. marotiri and S. dunedinensis.
References and further reading
Thompson, I.R. 2004: Taxonomic studies of Australian Senecio (Asteraceae): 1. The disciform species. Muelleria 19: 101-214.
This page last updated on 11 Aug 2014