The New Zealand Plant Conservation Network

Species

Simplicia laxa

Etymology

laxa: Slack, loose

Common Name(s)

Simplicia

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 - Threatened - Nationally Endangered

Qualifiers

2012 - CD, Sp
2009 - CD, Sp

Authority

Simplicia laxa Kirk

Family

Poaceae

Brief Description

Feeble, inconspicuous mat-forming grass of shaded habitats. Plants rooting at nodes. Leaf sheaths hairy. Inflorescences inconspicuous, delicate, pyramidal; flowering branches hairy, basal branches usually reflexed and spreading. Spikelets one-flowered, bearing prominent hairy lemma and much reduced, minute scale-like glumes.

Flora Category

Vascular - Native

NVS Species Code

SIMLAX

Structural Class

Grasses

Synonyms

Simplicia laxa Kirk var. laxa

Distribution

Endemic. South Island - Otago with one site at Honeycomb Cave, Karamea (de Lange et al. 2016).

Habitat

Simplicia laxa has been recorded from coastal to subalpine situations on base-rich rocks such as limestone, schist and basalt. All current populations grow on rock ledges, within crevices, overhangs and at cave entrances. It is suspected that the current habitats of Simplicia laxa are refugia, and that the species was once found in forested habitats (see de Lange et al. 2016).

Features

Plants trailing forming thick sprawling mats or diffuse interconnected patches up to 0.6 m across. Culms 0.40–0.80 m long, green to pale green when fresh, wiry, decumbent, with the apices weakly erect, culm internodes 4–8, elongated, sparsely (sometimes densely) hairy, or glabrous; hairs weakly flexuous, patent up 0.18 mm long; internodes usually shorter than subtending leaf-sheaths. Culm-nodes conspicuously swollen when fresh, maroon-black to black (0.13–)0.18–0.30 mm long, rooting freely on contact with ground. Basal leaf-sheaths glossy light brown to amber, membranous, ribbed, abaxially (often copiously) pubescent on ribs (and usually on interstices), hairs 0.20–0.25(–0.30) mm long, patent to retrorse; mid stem and upper leaf-sheaths pale-green to green, membranous, ribbed, abaxially pubescent on ribs (and sometimes on interstices), hairs copious, 0.35–0.40 mm long patent, mostly straight, sometimes curved or weakly flexuous. Ligule 2.8–3.5(–10) mm, membranous, lanceolate, apex erose to very deeply lacerate; abaxially sparsely to copiously hairy; hairs 0.20–0.24 mm long. Leaf-blade (100–)160(–200) × (2.8–)3.0(–3.6) mm, green to dark green, flat, linear-lanceolate, finely ribbed; adaxial ribs finely pubescent, abaxially glabrous (sometimes sparsely hairy at leaf base; margins ± smooth, sometimes irregularly finely scabrid and sparsely hairy. Panicle (40–)100(– 150) mm long, linear to ± pyramidal, usually with basal branch or branch pair reflexed (often unevenly so); rachis glabrous, branches (20–)40(–60) mm long, finely, antrorsely hairy (hairs 0.20–0.25 mm long), binate, initially contracted but as inflorescences mature, spreading to reflexed, devoid of spikelets in lower half; pedicels appressed to branchlets, 1.00–1.06 mm long, finely pubescent. Spikelets 2.8–3.2 mm, 1-flowered, lanceolate, light green. Glumes pale green (± hyaline), glabrous, broadly ovate-lanceolate to ovate, acute, 1-nerved, nerve extending beyond apex as a minute mucro, lower glume margins entire (sometimes with apex erose), ciliate towards apex, upper glume margins usually erose (sometimes subentire), ciliate; lower glume 0.5–0.8 mm, upper glume 0.75–1.0(–1.2) mm. Lemma 2.8–3.2(–3.4) mm, light green to grey-green (sometimes purple-green), ± evenly, densely pubescent, lanceolate, acute, apex mucronate (mucro 0.10–0.25 mm long), 3(–5)-nerved (nerves obscured by hairs); lemma hairs antrorse appressed, sericeous, 0.12–0.13 mm long. Palea 2.4–2.8 mm, lanceolate, pale green to green, pubescent, 1–2-nerved, (nerves obscured by hairs). Rachilla prolongation 1.25–1.30 mm, narrowly lanceolate, hyaline, margins minutely ciliate. Stamens 3. Filaments 0.20–0.25 mm long, hyaline. Anthers 0.30–0.45 mm, yellow. Ovary narrowly ovoid to weakly trigonous 1.0–1.25 mm long, dark green, ± glabrous (basal portion sometimes minutely ciliate); styles apical, 1.10–1.25 mm, hyaline; stigmas plumose, white. Caryopsis 1.4–1.5 mm long, laterally compressed, orange-brown when mature.

Similar Taxa

Allied to Simplicia felix from which it is distinguished by the mid-stem and upper stem leaf sheaths finely ribbed and copiously hairy; by the hairy adaxial leaf-blade ribs; by the antrorsely hairy inflorescence branches, longer pedicels 1.00–1.06 mm long and pubescent lemma (see de Lange et al. 2016). Simplicia felix and S. laxa differ from S. buchananii by the decumbent rather than tufted grwoth habit, spreadign to weakly ascendent rather thabn erect culms, by the nodes which root freely (plants thus forming nterconnected widely sprawling clonal patches) and by the linear to pyramidal, binate inflorescences, whose basal branch or branches are reflexed, and devoid of spikelets from lower half or so (see de Lange et al. 2016).

Flowering

November-March

Flower Colours

Green

Fruiting

January-May

Propagation Technique

Easy from rooted pieces. Can be grown from node cuttings. Often difficult to maintain in cultivation, and short-lived. It does best in a dry shady site, and should be planted in a free draining, lime-enriched soil.

Threats

Currently known from < 15 populations. Several of these are in decline, and very few are substantial in size. Many occur on private land without direct conservation management or in places subject to ongoing habitat deterioration through invasive weed pressure and habitat loss (for more information see de Lange et al. 2016).

Chromosome No.

2n = 28

Endemic Taxon

Yes

Endemic Genus

Yes

Endemic Family

No

This page last updated on 15 Dec 2016