Puccinellia walkeri
Common name
Walkers Saltgrass
Synonyms
Atropis walkeri (Kirk) Cheeseman; Glyceria novae-zelandiae Petrie; Atropis novae-zealandiae (Petrie) Hack.; Puccinellia novae-zealandiae (Petrie) Allan et Jansen; Puccinellia walkeri (Kirk) Allan subsp. walkeri
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.
PUCWAL
Chromosome number
2n = 35
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 | Range Restricted
Distribution
Endemic. New Zealand: South (Cook Strait (Brothers Islands), thence from Banks Peninsula to Riverton) and Stewart Islands
Habitat
On small islets and rock stacks (especially near sea bird nests) and in salt meadow, salt marsh and on saline ground in estuaries; also on sandy and stony ground at high tide level.
Features
Erect, bluish green or light green to pale brownish green, stiff, dense, very leafy tufts, 95-500 mm, with uppermost leaves usually overtopping culms; branching intravaginal. Leaf-sheaths straw-coloured to light greenish brown or grey-brown, sometimes purplish smooth, firmly membranous, finely nerved; ligule 0.6-3.0 mm, obtuse or truncate, or sometimes tapered at centre and acute, smooth, entire; leaf-blades 50-250 mm long, folded and then 5-10 mm wide, or sometimes almost flat, undersides smooth, upper shallowly ridged and sparsely scabrous on ridges, margins scabrous, tip smooth, ± firmly acute, sometimes subobtuse and ± apiculate. Culms smooth, usually enclosed by sheaths. Panicle 30-170 × 5-110 mm, initially overtopped by leaves usually expanding well above them at maturity, linear-lanceolate, erect, contracted, dense; branches stiff, erect, acute-angled and scabrous, spreading at maturity. Spikelets 3-9 mm, 2-5-flowered, bluish green or sometimes purplish. Glumes ± unequal, narrow-lanceolate to elliptic-oblong, subacute; lower glume 1.5-4.2 mm, 1-3-nerved; upper glume 2-5 mm, 3-5-nerved. Lemma 3-5 mm, 5-7-nerved, elliptic-oblong, apex subobtuse to obtuse, midnerve not excurrent, apex minutely ciliate-scabrous, otherwise with a few hairs on basal nerves and at base, sometimes with hairs on nerves to c.½ way. Palea < or occasionally = lemma, keels scabrous in upper ½-2/3, reaching only to palea-tip. Rachilla 0.8-1.8 mm. Anthers 0.6-l.5 mm. Seed 1.5-2.6 × 0.4-0.8 mm.
Similar taxa
Distinguished from P. antipoda (Petrie) Allan et Jansen and P. chathamica (Cheeseman) Allan et Jansen by the usually more robust growth habit, larger panicles with scabrous, acute-angled branches which when mature overtop the leaves, and from P. chathamica by the chromosome number (2n = 35 in P. walkeri, 2n = 42 in P. chathamica, P. antipoda is as yet uncounted). Differentiating between Puccinellia stricta and Puccinellia walkeri (which sometime co-occur) can be difficult: the size of the lemma (3-5mm in P. walkeri, usually less or = 3mm in P. stricta) is a good guide. The panicle of P. stricta also tends to open out post-flowering so that obvious branches are visible rather than remaining closely and erectly branched. The palea keel in P. stricta is scabrid but is ciliate in P. walkeri (though, this difference can be small).
Flowering
October - December
Fruiting
November - January (seed is absent in some populations)
Propagation technique
Easily grown from rooted pieces and fresh seed - when produced. Plants cultivated at the University of Auckland from several South Island locations proved to be pentaploid and did not produce viable seed.
Threats
Naturally Uncommon, range-restricted, sparse endemic. Very little is known about its ecology, and at least some populations appear to be sterile. However no obvious threats are known and the species is abundant in the southern part of its range.
Etymology
puccinellia: After the italian botanist Benedetto Puccinelli (1808 - 1850).
Where To Buy
Not commercially available
Notes
Edgar (1996) treated this species P. chathamica and P. antipoda as a subspecies of P. walkeri. Since that revision further research has elucidated that P. chathamica and P. walkeri have very different chromosome numbers and nrDNA ITS sequences. Although P. antipoda has not been available for study it would seem that subspecies rank is unjustified.
Attribution
Description modified from Edgar (1996).
References and further reading
Edgar, E. 1996: Puccinellia Part. (Gramineae: Poeae) in New Zealand. New Zealand Journal of Botany 34: 17-32.