Deyeuxia billardierei var. tenuis Cheeseman, D. tenuis (Cheeseman) Zotov
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.
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 | Threatened – Nationally Vulnerable | Qualifiers: RR
Previous conservation statuses
2012 | Threatened – Nationally Vulnerable | Qualifiers: RR
2009 | Data Deficient
2004 | Range Restricted
Apparently a local endemic. Confined to the South Island from Christchurch south along the Otago Coast to Bluff and on Stewart Island. At sites without grazing can be very common, though in the absence of a panicle it is very inconspicuous
Coastal scrub and open ground and at sea level in salt marshes and other estuarine habitats. In saltmarshes it appears to prefer vegetated slightly raised sandy ground. Often in association with Sellieria radicans. The detached panicles accumulate along the strand line of estuaries.
Stiff, leafy tufts 180-360 mm tall, leaves narrow, more or less inrolled, panicles lax. Branching intravaginal. Leaf-sheath subcoriaceous, more or less obviously ribbed, glabrous, light brown. Ligule 1.0-3.2 mm, truncate, erose, minutely ciliate, undersides scabrid. Leaf-blade 20-120 x 0.3-0.9 mm, inrolled, undersides smooth, rarely scabrid near apex, upper surface ribbed and short-scabrid on ribs, margins smooth, apex obtuse. Culm 50-200 mm, usually included within uppermost leaf-sheath, internodes densely, finely scabrid below panicle. Panicle 30-120 x 20-120 mm, delicate, branches fine, scabrid, erect to spreading, bearing spikelets at tips. Spikelets 3-5 mm, light green to light brown. Glumes 1-3-nerved, elliptic-lanceolate, more or less acuminate, strongly keeled, keel finely scabrid in upper half to two-thirds. Lemma 3.0-4.2 mm, more or less equivalent in length to glumes, firmly membranous, glabrous, papillose-scabrid, elliptic-lanceolate, lateral nerves sharply excurrent to c. 1mm; central awn 3.5-.6.5 mm, geniculate, emanating from lower one third of lemma. Palea 2.5-3.0 mm, c. two-thirds length of lemma, lanceolate, apex bifid, keels scabrid, margins submembranous, scabrid near apex. Callus hairs more or less dense, very short, 0.3-0.8 mm, about one quarter length of lemma. Rachilla prolongation 1.5-2.5 mm long, with very short hairs throughout except sometimes near tip, rarely completely glabrous. Lodicules 0.7-1.0 mm, lanceolate, acute. Anthers 0.5-0.9 mm. Seed 1.4-1.6 x 0.5-0.7 mm.
Manaaki Whenua Online Interactive Key
Distinguished from the other New Zealand species of the genus by the intravaginal branching; glabrous lemma, and inrolled leaf-blades, that are 0.3-0.9 mm diameter, spikelets 3-5 mm long, and lemmas that are papillose-scabrid throughout (hand lens needed). The combination of narrow filiform leaves (rarely flat and to 2mm wide), geniculate awn, and glabrous lemma (though care must be taken as the hairy rachilla can give the adaxial part of the lemma a hairy appearance)distinguishes this species from any other coastal Lachnagrostis.
Unknown, but probably easy from fresh seed and rooted pieces.
Threats to this species include grazing, competition with creeping bent (Agrostis stolonifera) and Elytrigia spp. Some salt marsh habitat has been lost through reclamation.
lachnagrostis: From “lachne” (wool) referring to the distinctive callus hairs of this genus and “agrostis” by which Trinius (1820) actually meant “a grass” (not an Agrostis). So the generic name means “a hairy (woolly) grass” not “a hairy (woolly) Agrostis” as is often incorrectly stated (see Gardner 2014).
Where To Buy
Not commercially available
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.