Pachycladon cheesemanii
Common names
dryland cress
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Flower colours
White
Detailed description
Robust, green, perennial herb, up to 500 mm tall. Basal leaves 15–80 mm long, simple, initially sparsely covered with branched hairs, becoming glabrescent with age; early basal leaves elliptic, entire or with a few blunt serrations, later leaves pinnatifid to pinnatisect, lobed 2–4 times in opposite to subopposite pairs; lamina, 10–60 × 8–30 mm; petioles 5–20 mm long. Stem leaves 1–4, lower ones similar to basal leaves, upper up to 10 × 3 mm, linear, minutely serrated. Inflorescences 150–500 mm long, up to 2.75 mm diameter at base, racemose; peduncle, pedicels, and siliques without glaucous bloom. Pedicels 10–15 mm long, glabrous. Sepals 3.3–3.5 x 1.4–1.5 mm, green with pale margins, oblong to elliptic, apex subacute. Petals 5.0–6.7 x 1.5–2.2 mm, white, obovate to obovate–spathulate, apex obtuse. Filaments 4–6, 3.3–4.2 mm long; anthers yellow. Ovary dorsiventrally compressed, green, glabrous; style indistinct, virtually absent; ovules 90–165. Siliques up to 60 mm long, green, without glaucous bloom, compressed, usually curved, glabrous. Seeds 0.8–1.1 mm long, pale brown, short–oblong.
Similar taxa
Most likely to be confused with the very similar Pachycladon exile (Heenan) Heenan et A.Mitch, which is a much smaller plant than P. cheesemanii with a circular ovary. P. exile is now only known from a single site in the Waitaki Valley (see fact sheet for that species for further information).
Distribution
Endemic. New Zealand: South Island (east of the main divide from Marlborough south to the northern portion of Southland).
Habitat
Lowland to subalpine tussock grassland, grey scrub, boulderfalls, talus, stable scree, rock overhangs and cliff faces. Now virtually confined to inaccessible habitats such as cliff faces, rock overhangs and amongst dense grey scrub.
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | Threatened – Nationally Endangered | Qualifiers: Sp, DPR, DPS, DPT, PF
Threats
Formerly widespread along the eastern side of the South Island from the Wairau River, Marlborough to northern Southland. Although it is still found within this range but populations usually small and widely scattered. The exact cause of its decline is not clear though it is palatable and browsing animals and introduced pests of brassiaceous crops may be partially responsible for its loss from some areas. Another probable factor in its decline has been the spread of naturalised plants into the open tussock grassland, stablised scree, talus and boulderfield habitats it once favoured. Many of the extant populations now occur in dark rock overhangs, where competition from the normally higher-light demanding weed species is less.
Detailed taxonomy
Family
Synonyms
Sisymbrium novae-zelandiae Hook.f., Ischnocarpus novae-zelandiae (Hook.f.) O.E.Schulz
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
September–February
Fruiting
October–March
Propagation technique
Difficult and should not be removed from the wild
Other information
Where To Buy
Not commercially available
Etymology
cheesemanii: Named after Thomas Frederick Cheeseman (1846 - 15 October 1923) who was a New Zealand botanist and naturalist who, in 1906, produced The Manual of the New Zealand Flora.
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
PACCHE
Chromosome number
2n = 20
Previous conservation statuses
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | Threatened – Nationally Endangered | Qualifiers: DP, RR, Sp
2012 | Threatened – Nationally Vulnerable | Qualifiers: Sp
2009 | Threatened – Nationally Vulnerable | Qualifiers: Sp
2004 | Gradual Decline
Regional conservation statuses
The regional threat classification system leverages off the national assessments in the NZTCS, providing information relevant for the regional context. Otago conservation status information is sourced from the “Regional conservation status of indigenous vascular plants in Otago” Jarvie S et al. (2024) report.
Otago: 2024 | Threatened – Regionally Endangered | Qualifiers: DPS, NStr, PF, RF
Referencing and citations
References and further reading
de Lange PJ, Heenan PB, Norton DA, Rolfe JR, Sawyer JWD. 2010. Threatened Plants of New Zealand. Canterbury University Press, Christchurch. 471 p.
Attribution
Fact Sheet prepared for NZPCN by P.J. de Lange 1 July 2007. Description by P.B. Heenan and published in de Lange et al. (2010)
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Pachycladon cheesemanii Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/pachycladon-cheesemanii/ (Date website was queried)