Puccinellia walkeri

  • Ligule. Papanui Inlet, Otago Peninsula
  • Caryopsis. Papanui Inlet, Otago Peninsula
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Species

Puccinellia walkeri

Etymology

Puccinellia: After the italian botanist Benedetto Puccinelli (1808 - 1850).

Common Name(s)

Walkers Saltgrass

Current Threat Status

2012 - At Risk - Naturally Uncommon

Previous Threat Status

2009 - At Risk - Naturally Uncommon
2004 - Range Restricted

Qualifiers

2012 - DP, Sp

Authority

Puccinellia walkeri (Kirk) Allan

Family

Poaceae

Flora Category

Vascular - Native

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

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.

Chromosome No.

2n = 35

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

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.

References and further reading

Edgar, E. 1996: Puccinellia Part. (Gramineae: Poeae) in New Zealand. New Zealand Journal of Botany 34: 17-32.

This page last updated on 14 Jan 2014

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