Sonchus novae-zelandiae

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Species

Sonchus novae-zelandiae

Etymology

Sonchus: sow thistle
novae-zelandiae: of New Zealand

Common Name(s)

Dryland sow thistle

Current Threat Status

2012 - Threatened - Nationally Vulnerable

Previous Threat Status

2009 - Threatened - Nationally Vulnerable
2004 - Sparse

Qualifiers

2012 - De, DP, Sp
2009 - DP

Authority

Sonchus novae-zelandiae (Hook.f) Garn.-Jones

Qualifiers

DP

Family

Asteraceae

Flora Category

Vascular - Native

Synonyms

Crepis novae-zelandiae Hook.f., Kirkianella novae-zelandiae (Hook.f.) Allan; Kirkianella novae-zelandiae f. minor Allan nom. inval. Kirkianella novae-zelandiae f. glauca Allan nom. inval.;

Distribution

Endemic. Three Kings Islands and South Island from the Marlborough Sounds to Southland and Fiordland.

Habitat

Coastal to subalpine (10 - 1200 m a.s.l.) amongst sea bird colonies or within open stony ground, short and tall tussock grassland, on or near rock outcrops (on rock ledges, within crevices, and on talus slopes), sometimes on recently exposed alluvium. Rarely in open ground under grey scrub.

Features

Rosulate, perennial, scapigerous herb arising from a stout, deeply descending, often multicipital tap root. All parts when broken leaking copious amounts of white latex exudate. Leaves and petiole 20-150 mm long, flattened, and more or less held appressed to the surrounding substrate; lamina crisply membranous, glabrous, lyrate, bright green, yellow-green, or glaucous, sinuately shallowly to deeply, closely or distantly lobulate, or pinnatifid; lobules rounded, apical, often mottled with darker brown pigmentation or glaucous; terminal lobes 30-50 x 20-30 mm, lateral lobes diminishing in size from 10 to 1 mm, confluent, merging into the broadly winged petiole. Scapes 150 mm or more long, slender, initially sparsely and finely tomentose, becoming glabrous, except near capitulum; bracteate, bracts 1-5, linear, tomentose mainly with eglandular hairs, glandular hairs either absent or sparse. Capitula 15-30 x 10-40 mm, receptacle shallowly concave, alveolate. Involucrum 4-seriate, imbricating, membranous with scarious margins; outer involucral bracts 3-5 mm long, narrow-ovate, undersides densely tomentose with dark spreading glandular hairs; inner bracts narrowly ovate-oblong up to 15 mm long, dark brown-green, undersides intially clad in white tomentum and glandular hairs becoming glabrous, margins scarious with rather fine teeth. Florets 30-36, ligulate; limb pale lemon-yellow, about equal in length to the slender claw, apex deeply 5-fid. Style arms long, densely covered in minute processes, finely coiled. Anthers conspicuous. Fertile achenes few, 2-3 mm long, dark brown, slightly compressed, broad at first, apices bluntly obtuse to rounded, narrowed slightly to base, crowned with minute asperities glabrous, primary ribs longitudinal, 4-5, prominent; secondary ribs 4-5, less obvious, otherwise strongly transversely wrinkled towards base. Sterile achenes numerous, narrowly subcylindric, pale and finely ribbed. Pappus hairs up to 7 mm long, copious, white, slender and soft, fused at base otherwise barbellate in upper half.

Similar Taxa

Sonchus novaezelandiae is set well apart from other members of Sonchus in New Zealand by its involucral bracts which are characteristically covered in dark, spreading glandular hairs, and often secondarily white tomentose (rarely glabrous), and by its flattened achenes, and slender white, fluffy, pappus hairs.

Flowering

November - April

Main Flower Colour

Yellow

Other Flower Colour

Black

Fruiting

November - May

Propagation Technique

Easy from fresh seed - the unusual foliage and colourful leaf markings make it a rather attractive pot plant or plant from a dry, free draining, sunny place in a rockery.

Threats

Sonchus novae-zelandiae appears to have always been biologically sparse but recent ad hoc field surveys for this species have found that it has declined from large parts of its former range. Many populations are at risk from the spread of Pilosella, and in some sites Sonchus novae-zelandiae is now confined to cliff and rock outcrop refugia

Chromosome No.

2n = 90, 126

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Where To Buy

Not commercially available.

Taxonomic notes

Allan (1961, Flora of New Zealand Vol. I, pp. 762-763) did not designate types or provide Latin diagnoses for his Kirkianella novae-zelandiae f. minor Allan and f. glauca Allan. These names are therefore illegitimate. Although Garnock-Jones (2014) published a new combination for Kirkianella in Sonchus a thorough study of the variation within that species is still required.

References and further reading

Allan, H.H. 1961: Flora of New Zealand. Vol. I. Wellington, Government Printer

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.

Garnock-Jones PJ. 2014: Evidence-based review of the taxonomic status of New Zealand's endemic seed plant genera, New Zealand Journal of Botany, DOI: 10.1080/0028825X.2014.902854

Heenan, P.B.; Mitchell, A.D.; de Lange, P.J.; Keeling, J.; Paterson, A.M. 2010: Late Cenozoic origin and diversification of Chatham Islands endemic plant species revealed by analyses of DNA sequence data. New Zealand Journal of Botany 48: 83–136.

Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285-309

 

This page last updated on 21 Nov 2016

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