Species
Senecio esleri
Etymology
Senecio: From the Latin senex 'old man' (probably referring to the bearded seeds)
Common Name(s)
Esler's fireweed
Current Conservation Status
2012 - Not Threatened
Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB
Previous Conservation Status
2004 - Exotic
Authority
Senecio esleri C.J.Webb
Family
Asteraceae
Flora Category
Vascular - Native
SENESL
The
National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
Structural Class
Dicotyledonous Herbs - Composites
Distribution
Indigenous. New Zealand, North Island from Te Paki to Rotorua (see de Lange 1997, 1995; P. J. de Lange unpubl. data). Also Australia, where it is an uncommon montane species of New South Wales and Tasmania
Habitat
Waste places and coastal habitats in Northland and the Auckland area. Especially roadsides, street margins, rock walls, waste places, gardens and sand dunes.
Features
Erect herb, usually annual, rarely a short-lived perennial, up to c. 2 m tall. Stems striate, often tinged purple, sparsely to densely setose especially above, branched above to form inflorescence. Lower cauline leaves almost glabrous to sparsely setose on upper surface, almost glabrous to moderately setose on lower especially on mid vein, apetiolate and longcuneate, 1-pinnatifid to 1/2-2/3 width, elliptic to narrow-obovate, acute at apex, c. 80-200 X 15-80 mm; segments narrow- to ovate-oblong, irregularly toothed; mid cauline leaves slightly larger, more deeply dissected with narrow-oblong toothed segments, sometimes amplexicaul and often 3-fid at base; uppermost leaves more ovate, sometimes with more or less linear segments. Capitula in loose panicles, 1-2 mm diameter. Supplementary bracts 3-10, lanceolate, ciliolate, 1-2 mm long. Involucral bracts (11>12-13, linear, usually glabrous, sometimes with a few scattered hairs, 4.5-5.5 mm long. Outer florets c. 24-35, female, filiform; inner florets c. 4-11, hermaphrodite, tubular. Achenes narrowly ellipsoid-cylindric, slightly narrowed and constricted below apex, with 2-3 rows of short antrorse hairs in grooves between or on edges of broad ribs and sometimes appearing evenly hairy, 2-2.3 mm long; pappus 5-7 mm long.
Similar Taxa
Senecio bipinnatisectus but can be distinguished from that species by the setose stems, less divided lower leaves, greater number of involucral bracts, and hairier achenes. S. hispidulus var. dissectus is also similar but this is immediately distinguished by the less dissected upper cauline leaves and the densely hispid upper surface of the leaf lamina. See Thompson, I.R. 2006: A taxonomic treatment of the tribe Senecioneae (Asteraceae) in Australia. Muelleria 24: 51–110.
Flowering
September to April
Flower Colours
Yellow
Fruiting
October to August
Propagation Technique
An aggressive weedy species. Senecio esleri grows quickly and rapidly from seed and prefers sunny, disturbed sites
Threats
Not Threatened
Endemic Taxon
No
Endemic Genus
No
Endemic Family
No
Comments
Senecio esleri was first described from New Zealand by Webb (1989) who considered it to be an introduced weed (but with little elaboration as to why), probably of Australian origin. Subsequently Thompson (2004) described the same species from Australia as S. brevitubulus I.Thomps. (not realising at the time that it had already been named from New Zealand material - see Thompson 2006). de Lange & Rolfe (2010) regard Senecio esleri as a recent indigenous natural arrival to New Zealand. It was first recorded in New Zealand from a remote part of Whangaruru Harbour, Northland in 1972 and it has subsequently spread from Northland south to Taupo.
Although weedy it is difficult to understand how such an uncommon montane Australian species could have been introduced to New Zealand by human agency (deliberate or accidental). Further, its pattern of arrival and spread is identical to many other "weedy" species accepted as indigenous, e.g., Picris angustifolia, Senecio hispidulus (glabrous form). One peculiar facet of New Zealand botany is the assumption that our indigenous flora is somehow static and so anything new (i.e. indigenous) that appears (meaning that it was not recorded by botanists working in the 1800s and early 1900s) and which is shared with Australia (or the South Pacific) is automatically naturalised. Heenan & de Lange (2009) argued that for those plants found within these regions and whose seed is suited to long distance dispersal, claims of indigenous or naturalised status needs to be carefully evaluated and explained on a case by case basis.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange (12 July 2005). Description based on Webb (1989)
References and further reading
de Lange, P.J. 1995: Senecio esleri makes it into the Waikato. Auckland Botanical Society Journal 50: 42-43.
de Lange, P.J. 1997: Senecio esleri straggles into Hamilton City. Auckland Botanical Society Journal 52: 26
de Lange, P.J.; Rolfe, J.R. 2010: New Zealand Indigenous Vascular plant Checklist. Wellington, New Zealand Plant Conservation Network
Heenan, P.B.; de Lange, P.J.; Keeling, J. 2009: Alternanthera nahui, a new species of Amaranthaceae indigenous to New Zealand. New Zealand Journal of Botany 47(1): 97–105.
Thompson, I.R. 2004: Taxonomic studies of Australian Senecio (Asteraceae): 1. The disciform species. Muelleria 19: 101–214.
Thompson, I.R. 2006: A taxonomic treatment of tribe Senecioneae (Asteraceae) in Australia. Muelleria 24: 65.
Webb, C.J. 1989: Senecio esleri (Asteraceae), a new fireweed. New Zealand Journal of Botany 27: 565-567.
This page last updated on 27 Oct 2016