Mitrasacme montana var. helmsii
Family
Loganiaceae
Flora category
Vascular – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Dicotyledonous Herbs other than Composites
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 | Threatened – Nationally Endangered | Qualifiers: DP, RR, Sp
Previous conservation statuses
2009 | At Risk – Naturally Uncommon
2004 | Range Restricted
Brief description
bronze green plants forming sprawling, diffuse patches and isolated tufts in open (sparsely vegetated) sodden ground. Stems up to 50 mm tall, leaves fleshy, spreading, 1.9–4.8 × 1.4–2.2 mm, obovate, with thickened margins and often minutely petiolate. Flowers white, tubular.
Distribution
Endemic. New Zealand: South Island, North Westland, Paparoa Ranges, Denniston and Stockton Plateaus
Habitat
Montane in wet tussock (Chionochloa juncea) grassland, cushion bogs, forming a sparse turf in sodden peaty skeletal quarzite soils or occurring in sparsely vegetated heath land
Features
Perennial plants forming bronze-green sprawling, diffuse patches and isolated tufts. Stems up to 50 mm tall. Leaves, fleshy, ± glabrous, ± petiolate to subsessile (mostly indistinct from lamina base), petiole 0.6-1.2 mm long, winged; lamina obovate, 1.9–4.8 × 1.4–2.2 mm; veins pinnately arranged; lamina margin thickened; base attenuate; apex obtuse or rounded. Bracts glabrous, scarcely distinguishable from leaves, 2.2–4.4 × 1.0–1.5 mm, narrowly obovate; apex obtuse or rounded. Flowers white, pedicellate or subsessile; pedicels glabrous, up to 0.5 mm long when flowering, elongating slightly at fruiting. Calyx tube 0.2–0.7 mm long; lobes unequal or equal, glabrous narrowly deltoid to narrowly ovate; apex acute or obtuse; larger pair 1.7–2.7 × 0.7–1.2 mm. Corolla tubular; tube 2.2–4.4 mm long; lobes 0.5–1.3 mm long, acute to obtuse. Styles 1.2–1.7 mm long. Capsule laterally flattened; 2.5–2.9 × 3.7–5.0 mm wide; locules elongate, oblique; distal portion of carpels free, divaricate, with wings forming a sheath between them; wings bilobed; styles persistent or withering somewhat in fruit, generally incurved. Seed 0.6–0.8 × 0.4–0.6 mm, oblong-elliptic, pale brown to brown.
Similar taxa
Distinguished from Mitrasacme novae-zelandiae var. novae-zelandiae by the weakly petiolate (rather than sessile), flexible obovate, spreading leaves with thickened margins (rarely with an indistinct hyaline), and tubular rather than bell-shaped flowers. Both Mitrasacme are sympatric in the Paparoa ranges, North Westland
Flowering
November-January
Flower colours
White
Fruiting
February-April
Propagation technique
Unknown
Threats
Although a biologically sparse, naturally uncommon plant because the majority of the known populations and much of the range of this variety is confined to the coal measures of the Denniston and Stockton Plateaus, and these habitats are being actively coal mined or at risk of future coal mining this variety is now assessed as ‘Threatened / Nationally Endangered’ (de Lange et al. 2013). Although Mitrasacme montana var. helmsii is known also from the Paparoa Ranges it is extremely uncommon there.
Etymology
mitrasacme: Mitre-tipped
montana: From the Latin mons ‘mountain’, meaning growing on mountains
Taxonomic notes
A full revision of the New Zealand Mitrasacme is required. When Dunlop (1996) erected the Australasian genus Schizacme they indicated that the New Zealand taxa Mitrasacme montana var. helmsii and M. novae-zelandiae var. novae-zelandiae were congeneric with Australian species of Schizacme but did not provide a formal treatment of them (Webb & Simpson 2001). Aside from the generic position, morphological evidence suggests that M. montana var. helmsii needs formal elevation to species rank, and further some Fiordland and Stewart Island populations currently attributed to M. novae-zelandiae var. novae-zelandiae may warrant segregation and formal taxonomic recognition.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange 12 November 2014. Description adapted from Kirk (1890), Allan (1961) and Webb & Simpson (2001), supplemented with observations made from dried material.
References and further reading
de Lange, P.J.; Rolfe, J.R.; Champion, P.D.; Courtney, S.P.; Heenan, P.B.; Barkla, J.W.; Cameron, E.K.; Norton, D.A.; Hitchmough, R.A. 2013: Conservation status of New Zealand indigenous vascular plants, 2012. New Zealand Threat Classification Series 3. Department of Conservation, Wellington.
Dunlop, C.R. 1996: Schizacme. Pp. 58-59, 314 in Orchard, A.E. (ed.) Flora of Australia. Vol 28: Gentianales. Melbourne, CSIRO publishing and Australian Biological Resources Study.
Kirk, T. 1890: On the occurence of a variety of Mitrasacme montana Hook.f. in New Zealand. Transactions and Proceedings of the New Zealand Institute 22: 445-446.
Webb, C.J.; Simpson, M.J.A. 2001: Seeds of New Zealand Gymnosperms and Dicotyledons. Christchurch, Manuka Press.
Citation
Please cite as: de Lange, P.J. (Year at time of access): Mitrasacme montana var. helmsii Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/mitrasacme-montana-var-helmsii/ (Date website was queried)