Species
Deyeuxia lacustris
Etymology
Deyeuxia: after Deyeux
lacustris: From the Latin lacus 'lake', meaning growing beside a lake
Common Name(s)
None known
Current Conservation Status
2012 - Threatened - Nationally Critical
Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB
Previous Conservation Status
2009 - Threatened - Nationally Critical
2004 - Range Restricted
Qualifiers
2012 - DP, RR, Sp
2009 - DP, RR, Sp
Authority
Deyeuxia lacustris Edgar et Connor
Family
Poaceae
Flora Category
Vascular - Native
DEYLAC
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.
Structural Class
Grasses
Synonyms
None (first described in 1999)
Distribution
Endemic. South Island only where it is currently known from two sites, Lake Sylvester, North West Nelson, and from the Tennyson Tarns and the shores of nearby Lake Tennyson
Habitat
Inhabiting the margins of kettle holes, tarns and montane to subalpine lakes. Sometimes found in damp seepages within tussock grassland.
Features
Tufted, reddish-green grass up to 300 mm tall. Culms erect over topped by dense, cylindric panicles, these much exceeding laves at maturity. Branching extravaginal. Leaf-sheath chartaceous, glabrous, light green to light reddish brown, ribs more prominent above. Ligule 2.3 mm, erose, tapering centrally to a fine tip, undersides smooth, upper surface slightly ribbed, sparsely scabrid on ribs; margins finely scabrid, apex cucullate. Culm 100-240 mm, erect or geniculate ta base, nodes hidden by leaf-sheaths, internodes glabrous. Panicle 15-45 x 5-8 mm, cylindric, compact, dense, glossy amber to purple-green; rachis smooth, branches and pedicels sparsely finely scabrid. Spikelets 5-7 mm, purplish green. Glumes subequal, 1-nerved, submembranous, elliptic-lanceolate, acute, smooth, keel finely scabrid on upper 2/3. Lemma 4-5 mm, 2/3-4/5 length of glumes, subcoriaceous, smooth below, finely papillose to prickle-toothed above, more or less elliptic, apex shortly bifid; awn 3.5-4.5 mm, from upper ¼ of lemma, twisted about twice at base, more or less recurved above. Palea c.2/3 length of lemma, hyaline, keels thickened, faintly prickle-toothed above. Callus hairs 0.3-1.0 mm. Rachilla prolongation 0.5-1.0 mm, bearing minute hairs throughout except at glabrous apex. Lodicules 0.4-0.5 mm long. Anthers 0.30-0.65 mm. Ovary 0.6 mm; stigma-styles 1.0-1.5 mm long. Seed 2.0 x 0.6 mm, with dehisced anthers entangled in stigma remnants.
Similar Taxa
Most likely to be confused with Deyeuxia avenoides (Hook.f.) Buchanan and D. youngii (Hook.f.) Buchanan. From D. avenoides (with which it grows) it can best be distinguished by the awn which arises from the upper 3/4 of the lemma rather than from the base, and by the rachilla which has a glabrous tip rather than a tuft of hairs equal to or slightly greater than the rachilla length. From D. youngii it can be dsitinguished by the callus hairs with are at least 1/3 rather than1/2 or more of the length of the lemma, and by the glabrous rather than hairy tip of the rachilla.
Flowering
November - January
Fruiting
December - April
Propagation Technique
Easy from fresh seed and division of whole plants but hard to maintain. Best grown in a pot. Despite its name it does not require damp conditions to thrive. Dislikes humidity.
Threats
Common at Lake Sylvester but very local at Lake Tennyson and the nearby tarns. There is some evidence that pasture grasses and weeds are a threat at the Tennyson tarns
Chromosome No.
2n = 56
Endemic Taxon
Yes
Endemic Genus
No
Endemic Family
No
Life Cycle and Dispersal
Florets are wind dispersed (Thorsen et al., 2009).
Where To Buy
Not commercially available.
Attribution
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 11: 285-309
This page last updated on 24 Jul 2014