Australopyrum calcis subsp. calcis
Common names
limestone wheatgrass
Biostatus
Native
Category
Vascular
Structural class
Grasses
Detailed description
Stout, stoloniferous red-green to dark green perennial grass. Leaf-sheath 25–50 mm, with retrorse short hairs, reddish green. Auricles 0.1–0.5 mm. Ligule 0.6–1.25 mm, lacerate. Collar dark brown to purple. Leaf-blade 60–250 × 0.5–3.5 mm, flat, thin, upper surface with minute prickle-teeth on ribs; underside with conspicuous white midrib and 2 lateral ribs. Culm 170–600 mm, slender, reddish, nodes swollen, dark-brown to black. Inflorescence a spicate raceme 30–130 mm; spikelets 4–13, overlapping; rachis internodes glabrous, margins toothed. Spikelets 10–14 mm. Glumes unequal, lower 2.5–4 mm, upper 3.7–5.5 mm, narrowly to broadly-triangular, 3–5-nerved, undersides prickle toothed, upper invested with short white hairs. Lemma 9–11 m; undersides with stiff 0.1 mm long teeth, awn 1.5–4 mm. Palea 5.3–7 mm, apex bidid. Callus 0.25–0.4 mm upperside with short stiff hairs. Anthers 2.4–2.8 mm. Ovary 0.8–1 mm, stigma-styles 1.8–2 mm. Seed 3.5–4 mm, linear.
Similar taxa
Australopyrum calcis subsp. optatum Connor et Molloy is a smaller and more slender grass. The upper surfaces of the leaves of this subspecies are distinctly, though finely, hairy (glabrous in Australopyrum calcis subsp. calcis), while the culm internodes are glabrous except for the last internodes below the inflorescence which is finely hairy (glabrous in Australopyrum calcis subsp. calcis). In this subspecies the inflorescence rachis is finely hairy while that of subsp. calcis is glabrous.
Distribution
Endemic. New Zealand, South Island, Marlborough. Known only from two sites in the Leatham Valley.
Habitat
Apparently a limestone endemic. The only known population grows mainly near a limestone outcrop in shaded sites under trees on lime-rich soils and limestone debris. However a very few plants grow directly on the limestone outcrop under shaded rock overhangs and ledges.
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – these interim threat classification statuses has not been assessed by the NZTCS panel.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | Threatened – Nationally Endangered | Qualifiers: CD, OL
Threats
Known from two extremely restricted sites in the Leatham Valley, South Marlborough. It is estimated that less than 200 plants are known from two sites in close proximity. The main population occurs at the base of a limestone bluff, while the other occurs along an old vehicle track at an adjacent limestone quarry. These populations are protected but are very vulnerable summer drought which can stress and even kill the overlying trees, thereby opening up the habitat to weeds. Although the grass is not especially palatable it is occasionally browsed by rabbits and hares.
Detailed taxonomy
Family
Poaceae
Synonyms
None
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
December–January
Fruiting
December–May
Propagation technique
Very easy from fresh seed. Does best in a pot. Can be grown in full sun or shade. Dislikes high humidity. Plants respond well to regularly applications of lime.
Other information
Manaaki Whenua Online Interactive Key
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.
AUSCSC
Chromosome number
2n = 14
Previous conservation statuses
2017 | Threatened – Nationally Endangered | Qualifiers: CD, OL, St
2012 | Threatened – Nationally Endangered | Qualifiers: CD, OL, St
2009 | Threatened – Nationally Endangered | Qualifiers: CD, St, OL
2004 | Threatened – Nationally Endangered
Referencing and citations
References and further reading
Edgar E, Connor HE. 2000. Flora of New Zealand. Vol. V. Grasses. Christchurch, Manaaki Whenua Press. 650 p.
Attribution
Description modified from Edgar and Connor (2000).
Some of this factsheet information is derived from Flora of New Zealand Online and is used under a Creative Commons Attribution 3.0 New Zealand licence.