Agrostis oresbia
Common name
mountain bent
Synonyms
None
Family
Poaceae
Flora category
Vascular – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Grasses
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.
AGRORE
Current conservation status
The conservation 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). 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.
2012 | At Risk – Naturally Uncommon | Qualifiers: DP, Sp
Previous conservation statuses
2009 | At Risk – Naturally Uncommon
2004 | Sparse
Distribution
Endemic. North Island (Raukumara, Ruahine and Tararua Ranges). South Island, North-West Nelson (Lake Aorere and Mt Domett only)
Habitat
A subalpine to alpine species frequenting damp seepages and water courses within tussock grassland and on rocky ground, shaded cliff faces or screes, occasionally on river flats.
Features
Tufted or stoloniferous plants 50-250 mm, culms overtopping leaves. Leaf-sheath hyaline, light green to light brown, prominently ribbed, smooth, rarely with prickle teeth. Ligule 1-4.5 mm, truncate to obtuse, denticulate or entire, glabrous. Leaf-blade 20-70 x 1.5-2 mm, flat or folded, undersides smooth, upper prominently ribbed, margins usually smooth, sometimes sparsely to densely, scabrid, apex tapered, blunt, scabrid. Culm erect, internodes glabrous. Panicle (15-)20-60 mm, open, lax, oblong to pyramidal, with spreading or flexuous branches; rachis smooth, branches and pedicels smooth or scabrid. Spikelets 2-2.5(-3) mm, purplish. Glumes unequal, acute to acuminate, keel scabrid near apex, margins smooth, sometimes scabrid near apex; lower, 2-2.5(-3) mm, ovate-lanceolate, upper 1.7-2.5(-3) mm, elliptic-lanceolate. Lemma 1.5-2 mm, glabrous, faintly 5-nerved, ovate, obtuse; awn (1.5-)2-3 mm, geniculate, slightly projecting beyond glumes. Callus with minute hairs. Anthers 0.4-0.9 mm.
Similar taxa
A. oresbia could be confused with A. magellanica Lam. but it is a smaller plant in all respects. It is perhaps closest to A. muelleriana Vickery from which it differs by its larger, more open, and laxer panicle, and by the glumes which are less scabrid and papillose. A. oresbia has a somewhat similar appearance to A. personata Edgar, from which it can be distinguished by its intravaginal innovations; awned lemmas; and by the abaxially smooth ligules. Palea 0.5 mm, ovate.
Flowering
unknown
Fruiting
unknown
Life cycle
Florets are dispersed by wind and water (Thorsen et al., 2009).
Propagation technique
Unknown but should be easy from fresh seed and rooted pieces
Threats
Not threatened but rather a naturally uncommon species of spradic occurrence which is why it has been listed
Etymology
agrostis: Greek name for a kind of grass
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange June 2005. Description modified from Edgar and Connor (2000).
References and further reading
Edgar, E.; Connor, H.E. 2000: Flora of New Zealand. Vol. V. Grasses. Christchurch, Manaaki Whenua Press. 650 pp.
Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 2009 Vol. 11 No. 4 pp. 285-309