Agrostis youngii Hook.f., Calamagrostis youngii (Hook.f.) Petrie, Calamagrostis petriei Hack., Deyeuxia petriei (Hack.) Cheeseman, Calamagrostis youngii var. petriei (Hack.) Petrie, Deyeuxia youngii var. petriei (Hack.) Cheeseman,
Vascular – Native
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.
2n = 28
Current conservation status
The threat classification status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley. Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – a suggested threat classification status has not been assessed by the NZTCS panel.
2017 | At Risk – Naturally Uncommon | Qualifiers: DP, Sp
Previous conservation statuses
2012 | At Risk – Naturally Uncommon | Qualifiers: Sp
2009 | At Risk – Naturally Uncommon
2004 | Sparse
Endemic. South Island only, where it is known from scattered sites from lake Sylvester (North West Nelson) south to Otago
Lowland to alpine. In forest clearings, tussock grassland, shrubland, boulderfield, on shaded bluffs, and along lake margins
Slender, tufts .3-1.3 m tall. Leaf-sheath papery, membranous, ribbed, glabrous or finely hairy, light green. Ligule 0.8-2.5 mm, truncate, ciliate to lacerate. Leaf-blade 120-350(-600) x 1-4 mm, stiff, flat or rolled, undersides smooth, upper ribbed, finely scabrid on ribs; margins finely scabrid, apex filiform, acute. Culm 0.4-1.15 m, nodes conspicuous, internodes usually smooth, sometimes scabrid near panicle. Panicle 70-160(-220) x 5-23 mm, linear-lanceolate, shortly and narrowly branched; rachis smooth, branches scabrid, pedicels slightly scabrid. Spikelets 4.5-7.5 mm, light green or purplish, crowded. Glumes 1-nerved, submembranous, elliptic-lanceolate, acute, scabrid, keel scabrid. Lemma (4-)5-6 mm, = glumes, scabrid, elliptic-lanceolate, apex denticulate; awn usually present, (0.5-)1-3 mm, straight, occasionally overtopping lemma apex. Callus hairs fine, covering (1/4)-½ lemma length. Rachilla prolongation 1.5-2.5 mm, surmounted by dense hair-tuft 2-3.5 mm. Anthers penicillate.
The narrow, cylindrical panicle place Deyeuxia youngii near Pentapogon avenoides, P. quadrisetus, and Deyeuxia lacustris. From these species it differs by the callus hairs extending for ½ the lemma length, and by the conspicuous hair tuft of the rachilla prolongation reaching the top of the lemma, or almost so. The lemma and rachilla prolongation characters place Deyeuxia youngii close to Deyeuxia aucklandica from which it differs by the linear-lanceolate panicle, lemma 4-6 mm long, and by the straight awn rarely projecting beyond the glumes. In some plants the callus hairs are reduced, but in these cases the short awn and penicillate anthers are distinctive.
October - February
October - March
Difficult. Dislikes humid climates.Can be grown from the division of whole plants and fresh seed but plants tend to be short-lived
Naturally uncommon and of sporadic occurrence. In some lowland locations it may be threatened by grassland weeds.
Where To Buy
Not commercially available
Description modified from Edgar and Connor (2000)
References and further reading
de Lange, P.J.; Schmid, L.M.H. 2022: New combinations in Pentapogon for Aotearoa / New Zealand taxa earlier placed in Deyeuxia (Poaceae). Ukrainian Botanical Journal 79(2): 73-76.
Edgar, E.; Connor, H.E. 2000: Flora of New Zealand. Vol. V. Grasses. Christchurch, Manaaki Whenua Press. 650 pp.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Pentapogon youngii Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/pentapogon-youngii/ (Date website was queried)