Species

Senecio kermadecensis

Etymology

Senecio: From the Latin senex 'old man' (probably referring to the bearded seeds)
kermadecensis: From the Kermadec Islands

Common Name(s)

Kermadec fireweed

Current Conservation Status

2012 - Threatened - Nationally Critical

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

2009 - Threatened - Nationally Critical
2004 - Threatened - Nationally Endangered

Qualifiers

2012 - CD, EF, IE, RR
2009 - De, DP, EF, IE, OL

Authority

Senecio kermadecensis Belcher

Family

Asteraceae

Flora Category

Vascular - Native

Structural Class

Dicotyledonous Herbs - Composites

Synonyms

Erechtites kermadecensis (Belcher) Allan

Distribution

Endemic to the Kermadec Islands where it has been reported only from Raoul and the nearby Meyer Islets. A specimen provisionally referred to S. kermadecensis from the Poor Knights Islands is best placed with S. minimus, which in New Zealand exists in two forms, a narrow-leaved form akin to the typical species, and a broad-leaved form, which is close to S. kermadecensis and appears to be a recent arrival to New Zealand from Australia. It is actively spreading in Northland. The Poor Knights collection is of that form.

Habitat

A species of disturbed sites, requiring open or clear ground such as that created by active sea bird nesting grounds to flourish.

Features

Erect annual or short-lived perennial herb. Stems usually dark maroon-purple, sometimes green. Basal leaves usually withering at flowering, apetiolate or shortly petiolate, 40–100 × 10–40mm, broadly elliptic, grey-green to bright green, sparsely to densely hispid especially on lower surface, evenly and finely dentate with dentitions increasing in depth toward leaf base; mid-cauline leaves similar, apetiolate, 30–80 × 5–30mm, broadly elliptic to elliptic, uppermost leaves smaller and narrower with few remote teeth. Inflorescence corymbose. Supplementary bracts of involucre 0–3, 1–2mm long. Involucral bracts 5–8, glabrous, 4.5–5.5mm long. Ray florets 0. Disc greenish-yellow, c. 1.5mm diameter. Cypsela subcylindric, 2.0–2.5mm long, greyish-black, scarcely narrowed or constricted at apex, with 1–3 rows of hairs in grooves between broad ribs.

Similar Taxa

Only known from the Kermadec Islands where it is the only erechtioid senecio species present. Young plants are hard to distinguish from Ageratum houstonianum, and reliable identification can only be made with flowering specimens. The flowers of Ageratum houstonianum are blue those of S. kermadecensis are yellow-green.

Flowering

August to January

Flower Colours

Green,Yellow

Fruiting

October to April

Propagation Technique

Easy from fresh seed but very cold sensitive.

Threats

Recent field surveys suggest this species is now confined to the Meyer Islets, where it is very common over a small area. Otherwise it seems to have gone extinct from Raoul Island over the last 30 years. The most likely cause of this decline seems to be the spread of the aggressive daisy Ageratum houstonianum Miller, which colonises the same open habitats the Senecio requires, is faster growing and seems to have displaced it from former and potential habitats on Raoul. Ageratum has now spread to the Meyer Islets, and eradication of this aggressive weed is unlikely due to the extreme vulnerability of the bird nesting grounds and burrows of those islands to collapse from human traffic.

Chromosome No.

2n = 60

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Where To Buy

Not commercially available.

 
  

Attribution

Fact Sheet prepared for NZPCN by P.J. de Lange 11 November 2008. Description based on Webb et al. (1988) supplemented with information obtained from fresh specimens and herbarium material.

References and further reading

Webb CJ, Sykes WR, Garnock-Jones PJ 1988. Flora of New Zealand. Vol. IV. Botany Division, DSIR, Christchurch.

This page last updated on 29 Apr 2014