Poa xenica
Synonyms
None (first described in 1999)
Family
Poaceae
Flora category
Vascular – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Grasses
Chromosome number
2n = 28
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.
2018 | At Risk – Naturally Uncommon
Previous conservation statuses
2012 | Data Deficient | Qualifiers: RR
2009 | At Risk – Naturally Uncommon
2004 | Range Restricted
Distribution
Endemic. New Zealand North-West Nelson (South Branch Riwaka River and Pikiruna Range (Gorge Creek)).
Habitat
Montane on marble cliffs in damp shaded sites and under associated sparse to moderately dense scrub on rubble fields
Features
Dioecious, glaucous to reddish-green, weakly tufted or pendulous, rather coarse, long-leaved plants, branching extravaginal, internodes elongate, rooting at nodes; leaf-blades persistent. Leaf-sheath 100 mm, keeled, ribbed, open to base, becoming dull brown and fragile, finely retrorsely hairy, margin membranous, darker brown. Ligule 1 mm, ciliate, abaxially finely hairy. Collar conspicuous, margin short hairy. Leaf-blade to 800 × 3-4 mm, coriaceous, folded below and at apex, ± flat elsewhere, abaxially glabrous with some long hairs near collar, adaxially clothed with small antrorse hairs, denser near ligule; margins abaxially sparsely prickle-toothed becoming smooth with apex prickle-toothed and sharp-pointed. Culm to 850, many noded, erect or with some geniculate nodes, nodes swollen, coloured, glabrous; internodes glabrous. Panicle to 250 mm, open, violet-suffused, subtended by bract to 2.5 mm; several to many solitary rarely binate branches at internodes, naked below with solitary spikelets, branches > internodes; rachis glabrous, branches and pedicels glabrous to sparsely shortly prickle-toothed. Spikelets 10-12 × 2 mm, gaping at anthesis, 1-6 widely separated florets. Glumes unequal, centrally green, violet elsewhere, nerves elevated; lower 2.5-3.5 mm, 1-3-nerved, upper 3.5-5.0 mm, 5-nerved, adaxially shortly hairy at apex, margins ciliate. Lemma 4.5-6.0 mm, 5-nerved, centrally green, violet elsewhere, abundantly finely pubescent throughout, keel prickle-toothed above, margins ciliate, membranous above, apex recurved, shortly lobed and mucronate, becoming erose. Palea 4.5-5.2 mm, less than or equal to lemma, apex bifid, keels minutely stiffly hairy. Callus 0.25 mm, short, blunt, glabrous or with a few prickle-teeth. Rachilla 1.5 mm, glabrous or with a few prickle-teeth at base; prolonged. Lodicules 0.5-1.0 mm, acutely lobed, tip ciliate. Anthers of male flowers: 2.75-3.75 mm, yellow or violet-suffused; of female flowers: 2.0-2.2 mm, white, pollenless. Gynoecium of male flowers: 0.8-1.0 mm; of female flowers: ovary 0.8-1.2 mm, glabrous; stigma-styles 2.0-3.5 mm. Seeds not seen.
Similar taxa
Poa xenica is most similar to P. anceps G.Forst. both species have a similar growth habit and extravaginal branching. However, P. anceps is monoecious and P. xenica dioecious. Vegetatively it is distinguished by the glaucous to reddish-green weakly tufted to pendulous foliage, leaf blades whose upper surface is distinctly ribbed rather than inconspicuously so, and smooth rather than covered in prickle teeth. Further the spikelets of P. anceps are 3.0-7.5 mm while those of P. xenica are 10-12 mm long.
Flowering
Unknown - insufficiently studied and collected
Fruiting
Unknown - insufficiently studied and collected
Propagation technique
Difficult. Has been grown from rooted pieces but dislikes drying out and humidity. Rarely flowers in cultivation. Best in a pot, partially submerged in water.
Threats
Not Threatened. However known from only three very small populations in what appear to be secure habitats
Etymology
poa: Meadow grass
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.