Myosotis hikuwai
Family
Boraginaceae
Flora category
Vascular – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Herbs - Dicotyledons other than Composites
Chromosome number
Unknown
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) – more information about this can be found on the NZTCS website. This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants.
Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – an interim threat classification status has not been assessed by the NZTCS panel.
- Conservation status of New Zealand indigenous vascular plants, 2017 . 2018. 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. Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | Threatened – Nationally Critical | Qualifiers: DP, OL
Brief description
In spite of its unusual erect habit spring annual
Distribution
South Island: Otago.
Habitat
On excessively well drained, gravelly alluvial outwash terrace bordering river, beside recreational track, in open kānuka shrubland and woodland; with Acaena agnipila, Carex breviculmis, Crassula mataikona, Hieracium lepidulum, Hydrocotyle moschata, Hypericum perforatum, Kunzea serotina, Myosotis brevis, Myosotis discolor, Myosotis glauca, Myosurus minimus subsp. novae-zelandiae, Veronica verna, and bryophytes.
Detailed description
Single rosette with fibrous roots, sometimes stoloniferous. Rosette leaves 5–6, petiolate; petioles not sheathing, 3.9–5.2 mm long, 0.6–2.3 mm wide; lamina 3.4–7.2 mm long, 2.1–3.3 mm wide (length:width ratio 1.3–2.7:1), widest point above middle, oblanceolate, narrowly obovate, obovate or broadly obovate; apex obtuse, with hydathode on abaxial side (rarely not visible); trichomes 0.3–0.7 mm long, mostly straight, some flexuous, adaxially antrorse, patent, oriented parallel or slightly oblique to the midrib, sparsely distributed, marginally antrorse, patent, sparsely distributed, rarely densely distributed, abaxially antrorse, appressed or patent, oriented parallel or oblique to the midrib, glabrous or with isolated trichomes; ratio of rosette-leaf trichome length to rosette-leaf length ~0.1:1. Inflorescences 1–5 per rosette, ascending to erect, once-branched or twice-branched, not bifurcating, up to 34–40 mm long, wholly bracteate, with up to 12–22 cauline leaves per inflorescence (including all branches) and of these, 12–20 associated with flowers; adventitious roots lacking at tips; scape 0.5–0.8 mm wide; trichomes 0.3–1.1 mm long, straight, rarely flexuous, antrorse, mostly patent, sometimes appressed, densely distributed. Lowest cauline leaves generally petiolate; petioles 3.3–4.9 mm long, 0.9–2.2 mm wide; lamina 4.7–5.9 mm long, 1.9–3.3 mm wide (length:width ratio 1.8–2.5:1), widest at or above middle, narrowly obovate, rarely oblanceolate; apex obtuse; trichomes as on rosette leaves. Uppermost cauline leaf sessile; lamina 1.5–3.2 mm long, 1.0–1.4 mm wide (length:width ratio 1.6–2.3, 1.9:1), widest above middle, rarely below middle, narrowly obovate, obovate, or narrowly ovate; apex acute; trichomes as on rosette leaves. Flowers up to 12–20 per inflorescence (including all branches). Internodes up to 2.1 mm long at flowering and up to 5.9 mm long at fruiting. Pedicels up to 1.1 mm at flowering or up to 1.4 mm at fruiting; trichomes 0.2–0.9 mm long, mostly flexuous, some straight, antrorse, appressed to patent, densely distributed and overlapping. Calyx 1.9–3.0 mm long at flowering, 3.4–4.7 mm long at fruiting, 1.5–2.0 mm wide at the top at fruiting; calyx lobes 1.1–2.2 mm long, 0.5–0.8 mm wide at fruiting, lobed to 0.3–0.5 × the length of the calyx; trichomes 0.1–1.2 mm long, flexuous mostly, antrorse, patent, densely distributed and sometimes overlapping, and inside sparsely distributed. Corolla 0.6–1.2 mm wide in diameter (measured, dried), 1.2–1.8 mm (calculated, dried), or 2.2–3.6 (measured, alive; G. Rogers, unpubl. data), white, with yellow faucal scales; corolla lobes 0.4–0.6 mm long, 0.4–0.5 mm wide (length:width ratio 1.0–1.4:1), obovate or very broadly ovate; corolla tube 1.5–2.1 mm long from base to faucal scales, 0.5–0.6 mm wide at faucal scales. Stamens ~2.4 mm long; filaments ~0.1 mm long, attached to corolla tube ~0.4–0.5 mm below base of faucal scales and 1.4– 1.8 mm from base of corolla tube; anthers 0.4–0.6 mm long, fully included, wholly below faucal scales. Style 1.3–1.8 mm long at flowering, 1.2–1.5 mm long at fruiting. Nutlets 4, 1.0–1.2 mm long × ~0.7 mm wide (length:width ratio 1.5–1.7:1), ovoid, keeled, rimmed or scarcely rimmed, light, medium or dark brown.
Similar taxa
Recognised by the erect growth and the spring annual lifestyle. Differs from M. antarctica, M. brevis, M. glauca and M. umbrosa in its erect habit and high number of cauline leaves subtending flowers; differs from M. glauca, M. antarctica and M. umbrosa by the combination of small corollas and nutlets (corolla diameter <1.5 mm, nutlets <1.2 mm long and <0.8 mm wide as measured on dried herbarium specimens) and patent trichomes on rosette leaf margins and adaxial surface; differs from M. brevis, M. antarctica and M. umbrosa by the mostly straight trichomes on many cauline- and rosette-leaf surfaces, and calyces with sparsely distributed trichomes; differs from M. brevis in its larger calyces (1.9–3.0 mm long at flowering and 3.4–4.7 mm long at fruiting).
Flowering
Spring annual; flowering mid-September–late November, fruiting November.
Etymology
myosotis: Mouse-eared
hikuwai: The epithet hikuwai refers to the Hikuwai Conservation Area where the only known population of this plant is from. In te reo Māori, hikuwai means ‘source of a stream' and may refer to the source of the Clutha River / Mata-Au.
It was first collected in 2013 and has been previously referred to as ‘Myosotis sp. morphologically similar to M. glauca’ (Prebble et al. 2018), M. aff. glauca (a) (WELT SP104520; “Mata-Au”) (de Lange et al. 2018; Prebble et al. 2022), or M. “Mata-Au” (Prebble et al. 2019).
Attribution
Fact sheet prepared by Marley Ford (8 April 2023). Distribution, Habitat, features and similar taxa sections copied from Meudt & Prebble (2022).
References and further reading
e Lange P. J., Rolfe J. R., Barkla J. W., Courtney S. P., Champion P. D., Perrie L. R., Beadel S.M., Ford K. A., Breitwieser I., Schönberger I., Hindmarsh Walls R., Heenan P. B., & Ladley K 2018. Conservation status of New Zealand indigenous vascular plants, 2017. (Department of Conservation: Wellington, New Zealand).
Meudt H. M., & Prebble J. M. 2018. Species limits and taxonomic revision of the bracteate–prostrate group of southern hemisphere forget-me-nots (Myosotis, Boraginaceae), including description of three new species endemic to New Zealand. Australian Systematic Botany 31, 48–105. doi:10.1071/SB17045
Meudt, H. M., & Prebble, J. M. 2022. Morphological analyses support recognition of three new threatened species of bracteate–prostrate Myosotis (Boraginaceae) endemic to the South Island of Aotearoa New Zealand. Australian Systematic Botany, 35(5), 364-394.
Prebble J. M., Meudt H. M., & Tate J. A., & Symonds V. V. (2018) Bolstering species delimitation in difficult species complexes by analyzing herbarium www.publish.csiro.au/sb Australian Systematic Botany 393 and common garden morphological data: a case study using the New Zealand native Myosotis pygmaea species group (Boraginaceae) and common garden morphological data: a case study using the New Zealand native Myosotis pygmaea species group (Boraginaceae). Systematic Botany 43, 266–289. doi:10.1600/036364418X697058
Prebble J. M., Meudt H. M., Tate J. A., & Symonds V. V. 2019. Comparing and co-analysing microsatellite and morphological data for species delimitation in the New Zealand native Myosotis pygmaea species group (Boraginaceae). Taxon 68, 731–750. doi:10.1002/tax. 12096
Prebble J. M., Symonds V. V., Tate J. A., & Meudt H. M. (2022) Taxonomic revision of the southern hemisphere pygmy forget-me-not group (Myosotis; Boraginaceae) based on morphological, population genetic and climate-edaphic niche modelling data. Australian Systematic Botany 35(1), 63–94. doi:10.1071/SB21031