Rytidosperma nudum
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Grasses
Detailed description
Diminutive, diffuse tufted grass, leafy at ends of elongating shoots, rooting at nodes; leaves somewhat acute, more or less equal to culms, dis-articulating at ligule. Branching intravaginal. Leaf-sheath pale straw-coloured to light grey, glabrous; apical tuft of hairs few, 1–2 mm long. ligule to 0.4 mm. Leaf-blade to 80 mm, folded, narrow, rather soft, glabrous. Culm to 100 mm, internodes glabrous. Panicle small, erect, to 30 mm, of few spikelets on short pedicels; rachis and pedicels slender, closely short-scabrid and some longer hairs at branch axils. Spikelets usually 3-flowered, awns barely exserted from glumes. Glumes purplish centrally, ovate, obtuse, more or less equal, 3.5–7.0 mm long; lower 3–5-nerved, upper 3-nerved. Lemma 2.3–3.5 mm, 5–9-nerved, upper and lower rows of hairs very sparse, upper row usually of small marginal tufts with a few scattered hairs, elsewhere glabrous, margins with scattered hairs; lobes 0.2–0.5 mm, acute to acuminate, not awn-tipped; central awn 1–2 mm long, erect, column scarcely evident. Palea 2.4–2.8 mm long, reaching base of awn, sinus, = upper lemma hairs, inter keel glabrous, margins occasionally with a few long hairs. Callus c. 0.3 mm long, a few marginal hairs not reaching lower lemma hairs, or marginal tufts denser, slightly overlapping lower lemma tufts. Rachilla 0.5–0.8 mm. Anthers 0.7–0.8. Seed not seen.
Similar taxa
Recognised by the awn of the lemma 1–2 mm long, and the lemma which is 2.3–3.5 mm, 5–9-nerved, with the upper and lower rows of hairs very sparse, and the upper row usually comprised of small marginal tufts with a few scattered hairs, otherwise glabrous. The lemma margins have scattered hair and lobes 0.2-0.5 mm, which are acute to acuminate. Its relationship to the other indigenous species is not clear though it seems closest to R. australe and R. pumilum. The small, few-flowered spikelets and absence of seed are useful field characters.
Distribution
Endemic. North Island, Central Volcanic Plateau (Mt Ruapehu), Ruahine and Tararua Ranges.
Habitat
Subalpine to alpine in flushes and bogs.
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 | At Risk – Naturally Uncommon | Qualifiers: RR
Threats
A very local endemic, rarely collected.
Detailed taxonomy
Family
Synonyms
Danthonia nuda Hook.f., Notodanthonia nuda (Hook.f.) Zotov
Taxonomic notes
Some botanists believe that this uncommon species is a naturally occurring, uncommon, sterile hybrid (B.P.J. Molloy pers. comm.; de Lange et al. 2009; de Lange & Rolfe 2010), especially as the seed of this species has never been seen. However, the recent (2012) discovery of this species growing in abundance in alpine flushes on Mt Ruapehu (P.J. de Lange, N.J. Singers, J.R. Rolfe & M.A.M. Renner unpubl. data), in morphologically uniform populations suggests that it is a functional species. Currently this species is listed as Taxonomically Indistinct in Appendix 3 of de Lange et al. (2009) having previously been listed as “Range Restricted” by de Lange et al. (2004). Clearly this status will need to change and as as an interim measure the status of “At Risk / Naturally Uncommon” appended DP [Data Poor], RR [Range Restricted] is here suggested (P.J. de Lange unpubl. data).
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
November–January
Fruiting
Not known
Propagation technique
Grows easily enough from the division of whole plants
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
OBL: Obligate Wetland
Almost always is a hydrophyte, rarely in uplands (non-wetlands).
Other information
Etymology
rytidosperma: Wrinkled seed
nudum: Bare
Manaaki Whenua Online Interactive Key
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.
RYTNUD
Chromosome number
2n = 24
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 | At Risk – Naturally Uncommon | Qualifiers: RR
2012 | At Risk – Naturally Uncommon | Qualifiers: RR
2009 | At Risk – Naturally Uncommon | Qualifiers: DP, RR
2004 | Range Restricted
Referencing and citations
References and further reading
de Lange PJ, Norton DA, Heenan PB, Courtney SP, Molloy BPJ, Ogle CC, Rance BD, Johnson PN, Hitchmough R. 2004. Threatened and uncommon plants of New Zealand. New Zealand Journal of Botany 42: 45–76.
de Lange PJ, Norton DA, Courtney SP, Heenan PB, Barkla JW, Cameron EK, Hitchmough R, Townsend AJ. 2009. Threatened and uncommon plants of New Zealand (2008 revision). New Zealand Journal of Botany 47: 61–96.
de Lange PJ, Rolfe JR. 2010. New Zealand Indigenous Vascular Plant Checklist. New Zealand Plant Conservation Network, Wellington. 164 p.
Edgar E, Connor HE. 2000. Flora of New Zealand. Vol. V. Grasses. Manaaki Whenua Press, Christchurch, NZ. 650 p.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange 30 August 2006. Description adapted from Edgar & Connor (2000).
Some of this factsheet information is derived from Flora of New Zealand Online and is used under a Creative Commons Attribution 3.0 New Zealand licence.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Rytidosperma nudum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/rytidosperma-nudum/ (Date website was queried)