The New Zealand Plant Conservation Network

Species

Pachycladon stellatum

Etymology

stellatum: With spreading, star-like rays

Common Name(s)

starry cress

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 - Serious Decline

Qualifiers

2012 - DP
2009 - DP

Authority

Pachycladon stellatum (Allan) Heenan et A. Mitch.

Family

Brassicaceae

Flora Category

Vascular - Native

NVS Species Code

PACSTE

Structural Class

Dicotyledonous Herbs other than Composites

Synonyms

Cheesemania fastigiata var. stellata Allan, Cheesemania stellata (Allan) Heenan et Garn.-Jones; Pachycladon stellata (Allan) Heenan et A. Mitch. orth. var.

Distribution

Endemic to the upper reaches of several river systems of inland South Marlborough and the Kaikoura Ranges and Upper Awatere.

Habitat

Upland to subalpine rocks, on ledges, crevices, cracks and overhanging bluffs. Often found on shaded, south-facing sites.

Features

Polycarpic perennial rosette-forming herb, up to 340 mm tall; rootstock stout, up to 16 mm diameter. Rosette, densely leafy, foliage coriaceous, dull, grey-green, often red-purple on petiole and lower surface. Leaves 20–80 × 5–19 mm, narrow-lanceolate, lanceolate, or oblanceolate, shallowly serrate with 4–8 pairs of teeth; apex acute to subacute; base attenuate. Hairs on leaves and inflorescence bifurcating, dendritic, sometimes simple, white or sordid, harsh or scabrid. Inflorescence 150-350 mm, compound, with terminal and lateral racemes, lateral racemes alternate and occasionally with secondary racemes. Cauline leaves subtending lateral racemes and rarely lowermost flowers, 3.5–55 × 1–5 mm, similar to rosette leaves, becoming smaller and linear up stem, moderately to densely hairy; base cuneate to subauriculate . Racemes 60-200 mm long at fruiting, 10-40-flowered; sparsely to densely covered in hairs. Pedicels 4.0-5.5 mm long at flowering, 7–15 mm long at fruiting, usually glabrous, suberect to erecto-patent. Sepals 3.5–4.5 × 1.3–2.1 mm, ascending, green, oblong, with few hairs, often flushed pink in bud; margin broad, membranous, white; apex obtuse to subacute. Petals 6–7 × 3–4 mm, white; claw 2.0–3.5 mm long; limb broad elliptic to obovate, or short oblanceolate, 3.0–3.5 mm long; apex rounded; base attenuate to cuneate . Stamen filaments 2.5–4.9 mm long; anthers 0.9–1.1 × 0.5–0.6 mm, white. Nectary almost surrounding the bases of the lateral stamens. Ovary 2.6–4.1 × 0.5–0.8 mm, green, glabrous. Style 0.3–0.7 mm long . Stigma 0.4–0.5 mm wide. Siliques 30–60 × 1.3–2.3 mm, linear, valves weakly keeled at base, 1-veined, at maturity yellow-brown and often flushed red-brown . Septum intact, with or without a midvein. Funicle 0.3–0.5 mm long. Seeds 30–50 per locule, 1.1–1.4 × 0.5–0.7 × 0.3–0.4 mm, oblong to narrowly ellipsoid, flattened, brown or red-brown; surface regular to irregular, reticulate; wing usually apical but sometimes decurrent on apical half of seed, 0.2–1.0 mm long at seed apex.

Similar Taxa

Pachycladon stellatum could be confused with P. enysii and P. fastigiata. Pachycladon stellatum has grey-green leaves with shallow regular lobes, dense star-shaped hairs and long flowering stems. P. fastigiata has sharply-toothed leaves. P. enysii has short flower stems. In general, readily distinguished from other rossette-forming Pachycladon by the narrow lanceolate to oblanceolate, serrate, grey-green leaves which are densely covered in small bifurcating and dendritic hairs.

Flowering

November to January

Flower Colours

Green,White

Fruiting

January to April

Propagation Technique

Difficult. Should not be removed from the wild.

Threats

A rather localised species, which is unusual for the genus in that it extends from montane to lowland cliff and rock outcrop habitats. In these sites plants are vulnerable from weed competition, browsing animals such as goats, and plant collectors. At least one population has gone extinct through the actions of plant collectors. Most of the known sites are small and mature reproductive individuals are scarce. Indications are that many of the known populations are declining rapidly, though the exact cause(s) is/are unknown.

Chromosome No.

2n = 20

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 4 Sep 2013