Species

Senecio esperensis

Etymology

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

Common Name(s)

L Esperance Rock groundsel

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 - Range Restricted

Qualifiers

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

Authority

Senecio esperensis (Sykes) de Lange

Family

Asteraceae

Flora Category

Vascular - Native

Structural Class

Dicotyledonous Herbs - Composites

Synonyms

Senecio lautus subsp. lautus var. esperensis Sykes, Senecio lautus var. esperensis Sykes; Senecio lautus subsp. esperensis (Sykes) de Lange

Distribution

Endemic. Kermadec Island group, known only from the summit slopes and crater of L Esperance Rock.

Habitat

The summit of L Esperance Rock (also known as French Rock), where it only grows in volcanic tuff and guano deposits.

Features

Annual glabrous, succulent herb up to 1.2 m tall. Stem simple, occasionally branched, erect. Leaves initially petiolate toward stem base becoming sessile then auriculate, ultimately stem clasping toward stem apex; lamina up to 230 × 40mm, glossy dark green above, paler and dull beneath, succulent, oblong-spathulate, irregularly serrate to lobulate with teeth to 5mm long but never deeply pinnatifid. Inflorescence terminal with 1 or more branches. Capitula 10–12, usually widely spaced in a loose head. Involucral bracts 8–9(-13), pale green to dark green, 5–7mm long, margins scarious, apex acute. Ray florets 8–10, ligules 1.6–3.25mm long, yellow, somewhat revolute. Disc florets 4mm long. Cypsela 2.5mm long, dark brown, cylindrical, shallowly ribbed, with sparse hairs in grooves

Similar Taxa

Senecio lautus is superficially similar. S. esperensis. Senecio esperensis differs from S. lautus by the taller stature, sparingly branched growth habit, leaves which are never as deeply pinnatifid as those of S. lautus, by the capitula which have fewer involucral bracts and by the sparsely hairy cypsela. S. lautus is endemic to the main islands of New Zealand and is not known from the Kermadec Island group. In many respects Senecio esperensis has a closer resemblance to S. sterquilinus from which it differs by its much great size, less deeply divided leaves and sparsely hairy cypsela (for more details see de Lange et al. 2015).

Flowering

September - October (depending on local conditions)

Flower Colours

Green,Yellow

Fruiting

September to December (depending on local conditions)

Propagation Technique

Easily grown from fresh seed, however, plants cultivated in Auckland in 2011 all died at the onset of flowering from Phytophora (de Lange 2015).

Threats

The only known habitat is a nature reserve remote from main shipping routes so the rock is rarely visited. For emergency purposes the summit of the island was used as a fuel dump for rescue helicopters. Ironically there is where the Senecio mainly grows. In May 2011 a visit to L'Esperance by Department of Conservation staff found the Senecio to be locally common, they also found no sign of the helicopter platform or fuel dump - these appeared to have been washed away by Cyclone Bune which struck the Kermadec Islands in March 2011 (de Lange 2015). Senecio esperensis qualifies as Nationally Critical because of its small area of occupancy (de Lange 2015 (as S. lautus subsp. esperensis) and de Lange et al. 2015).

Chromosome No.

2n = 40

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Taxonomic Notes

Senecio esperensis was originally described as a variety of S. lautus (Sykes 1971) and then it was elevated to subspecies rank by de Lange et al. (2010). However, on further study using wild collected and cultivated plants it became evident that this plant is worthy of species rank (de Lange 2015) and as such the necessary combination at that rank has now been made (de Lange et al. 2015)

Attribution

Fact Sheet prepared by P.J. de Lange 11 November 2008. Description from de Lange et al. (2015)

References and further reading

de Lange PJ 2015. The flora and vegetation of L’Esperance Rock, southern Kermadec Islands
group. Auckland Museum Bulletin 20: 231–242.

de Lange in: de Lange, P.J.; Heenan, P.B.; Norton, D.A.; Rolfe, J.R.; Sawyer, J.W.D. 2010: Threatened Plants of New Zealand. Canterbury University Press, Christchurch.

de Lange, P.J.; Liew, C.S.; Rolfe, J.R.; Pelser, P.B. 2015: Senecio esperensis (Asteraceae: Senecioneae)—a new combination for the L'Esperance Rock groundsel, Kermadec
Islands. New Zealand Journal of Botany, DOI: 10.1080/0028825X.2015.1039552

Sykes, W. R. 1971: Senecio lautus in the Kermadec Islands. New Zealand Journal of Botany 9: 533–538.

This page last updated on 26 Aug 2015