The New Zealand Plant Conservation Network

Species

Notothlaspi viretum

Etymology

Notothlaspi: southern cress
viretum: Meaning 'grass green'

Authority

Notothlaspi viretum Heenan

Family

Brassicaceae

Brief Description

Alpine herb forming compact green cushions on ultramafic rocks. Cushions comprised of numerous closely placed rosettes. Leaves narrowly linear to lanceolate (when bruised smelling of cress), bright green. Flowers white. Fruit a green silicle.

Flora Category

Vascular - Native

Structural Class

Dicotyledonous Herbs other than Composites

Synonyms

None - first described in 2019

Distribution

Endemic. New Zealand, South Island, Richmond Range (Red Hills)

Habitat

Known only from one site between 1540–1700 m a.s.l. where the species is confined to rocky outcrops, sparsely vegetated open stable to semi-stable scree, and on coarse sand and soil derived from ultramafic harzburgite rock.

Features

Perennial herb, with short lateral stems, stems 1.0–1.7 mm diameter, usually forming compact cushions of few to numerous rosettes. Leaves 9.0–26.0 mm long, rosulate or spreading on stems; lamina 7.0–17.0 mm long, 0.7–2.4 mm wide, linear to linear-narrowly lanceolate, green, coriaceous, glabrous on abaxial and adaxial surfaces; margin usually entire, occasionally 1-pinnatafid; apex attenuate, tip obtuse with a prominent hydathode, base attenuate; petiole 2.0–10.0 mm long, often indistinct from lamina. Inflorescence axillary, flowers solitary; peduncle 7–10 mm long, 0.4–1.0 mm diameter, ascending, glabrous. Sepals 3.7–4.5 mm long, 1.2–1.5 mm wide, linear-lanceolate, green, glabrous, margin entire, apex subacute, base truncate. Petals 5.5–6.5 mm long, 1.6–2.4 mm wide, white, limb obovate to broadly elliptic, patent to reflexed; apex obtuse; base cuneate, tapering to a 2–3 mm long claw. Stamens 6; filaments linear, two 2.4–4.0 mm long, four 3.4–5.4 mm long; anthers 0.9–1.0 mm long, cream to pale yellow. Ovary 2.2–3.0 mm long, 1.2–1.8 mm wide, compressed, green, glabrous; ovules 5–8 per locule; style 2.0–2.1 mm long, terete; stigma capitate, 0.4–0.5 mm diameter. Silicle 4.3–5.2 mm long, 4.5–5.1 mm wide, green, glabrous, obcordate, angustiseptate; valves keeled, winged, wing c. 0.5 wide at base, up to 2.3 mm wide at apex, wing extended to form an apical notch to silicle; style persistent, up to 1.2 mm long. Seeds 0.8–1.1 mm long, 0.6–0.9 mm wide, orbicular-oblong, brown.

Similar Taxa

An ultramafic endemic that is distinguished from Notothlaspi australe by the compact cushion growth habit with the plants producing numerous closely placed rosettes; by the green, linear to linear-narrowly lanceolate leaves that are 7.0–17.0 mm long and 0.7–2.4 mm wide.

Flowering

December - January

Flower Colours

White

Fruiting

Ferbuary - April

Propagation Technique

Not known from cultivation.

Threats

As Notothlaspi (a) (CHR 363071; Red Hills) N. viretum was assessed as having a conservation status of Threatened, Nationally Critical by de Lange et al. (2018). This assessment considers that Notothlaspi viretum is confined one location with an area of occupancy  less than or equal to 1.0 hectare. Currently the sole known population is believed stable. Heenan (2019) suggest that hybridisation with N. australe may pose a long term threat as N. viretum is sympatric with N. australe and plants possibly representing hybrids were observed during a visit to the type locality in April 1997.

Chromosome No.

2n = 90-100

Endemic Taxon

Yes

Endemic Genus

Yes

Endemic Family

No

This page last updated on 5 Sep 2019