# Myosotis arnoldii

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Species of flowering plant

Myosotis arnoldii Herbarium specimen of Myosotis arnoldii plant collected in 2013 WELT SP100473 Conservation status Naturally Uncommon (NZ TCS)[1] Scientific classification Kingdom: Plantae Clade: Embryophytes Clade: Tracheophytes Clade: Spermatophytes Clade: Angiosperms Clade: Eudicots Clade: Asterids Order: Boraginales Family: Boraginaceae Genus: Myosotis Species: M. arnoldii Binomial name Myosotis arnoldii L.B.Moore[2]

***Myosotis arnoldii*** is a species of [flowering plant](/source/Flowering_plant) in the [family](/source/Family_(taxonomy)) [Boraginaceae](/source/Boraginaceae), [endemic](/source/Endemic_species) to the [South Island](/source/South_Island) of [New Zealand](/source/New_Zealand). [Lucy Moore](/source/Lucy_Moore_(botanist)) described the species in 1961. Plants of this species of [forget-me-not](/source/Forget-me-nots) are [perennial](/source/Perennial_plant) rosettes with ebracteate inflorescences, corollas ranging from yellow to dark purple, and stamens that are wholly exserted.

## Description

*Myosotis arnoldii* plants are rosettes. The rosette leaves have broad [petioles](/source/Petiole_(botany)) that difficult to distinguish from the leaf blades. The rosette leaves are 30–70 mm long by 5–9 mm wide (length: width ratio ca. 3–7: 1), linear-spathulate or oblanceolate, and widest at or above the middle, with an [subacute](/source/Acute_(botany)) to [obtuse](/source/Obtuse_(leaf)) apex. Both surfaces of the leaf are uniformly and densely covered in straight, appressed, white hairs that completely cover the underlying leaf surface**.** Each rosette has several erect, ebracteate [inflorescences](/source/Inflorescence) that are up to 180 mm long. The cauline leaves are similar to the rosette leaves, but smaller, are narrow-oblong and subacute, and have hairs similar to the rosette leaves.

The flowers are many per inflorescence, and each is borne on a short [pedicel](/source/Pedicel_(botany)), each with a bract. The calyx is c. 8 mm long at flowering and fruiting, lobed to one-half of its length, and densely covered in straight, appressed antrorse hairs, as well as some erect hooked hairs near the base. The corolla is yellow to dark purple, "deeply coloured", and about 8–10 mm in diameter, with a cylindrical tube, and small scales alternating with the petals. The anthers are exserted with the anthers surpassing the faucal scales. The nutlets were not described.[3] Flowering occurs between October and January and fruiting from December to May.[3]

## Taxonomy

*Myosotis arnoldii* is in the plant family [Boraginaceae](/source/Boraginaceae) and was originally described in 1961 by [Lucy Moore](/source/Lucy_Moore_(botanist)) in the *Flora of New Zealand*.[2][3]

The original specimens ([isotypes](/source/Isotype_(biology))) of this species were collected by [Arnold Wall](/source/Arnold_Wall) from "Ben More, Ure River, [Marlborough](/source/Marlborough_District)", South Island, New Zealand.[2] The specimens collected by Wall are housed are lodged at the [Museum of New Zealand Te Papa Tongarewa](/source/Museum_of_New_Zealand_Te_Papa_Tongarewa), Wellington (herbarium WELT).[2][4][5]

The specific epithet, *arnoldii*, is named after Arnold Wall (1869 – 1966), a New Zealand botanist who made the first collections.[2]

Lucy Moore suggested that *Myosotis arnoldii* is morphologically most similar to *[M. angustata](/source/Myosotis_angustata)* and *[M. macrantha](/source/Myosotis_macrantha)* based on habit and leaves, and to *[M. albosericea](/source/Myosotis_albosericea)* based on the very dense covering of white, appressed hairs on its vegetative parts including the rosette and stem leaves, which completely obscure the epidermis.[2] These hairs are antrorse (forward facing), straight, and on the leaf are oriented parallel to the midrib. The only other New Zealand species with such hairs is *Myosotis albosericea,* [endemic](/source/Endemism) to southern South Island, New Zealand.[6]

### Phylogeny

No individuals of *M. arnoldii* were included in [phylogenetic](/source/Phylogenetics) analyses of standard DNA sequencing markers ([nuclear ribosomal DNA](/source/Ribosomal_DNA) and [chloroplast DNA](/source/Chloroplast_DNA) regions) of New Zealand *Myosotis.[7][8]* In those studies, within the southern hemisphere lineage, species relationships were not well resolved.[7][8]

Three individuals from one population of *M. arnoldii* were also genotyped in a study that developed microsatellite DNA markers for another species group of New Zealand *Myosotis.*[9][10] The individuals of *M. arnoldii* included showed a high number of alleles that cross-amplified at most of the microsatellite loci.[10]

## Distribution and habitat

*Myosotis* *arnoldii* is a [forget-me-not](/source/Forget-me-not) is known to occur in two disjunct populations in the northern part of the South Island, New Zealand.[3][11] This species grows on cliff faces and other rocky habitats on marble substrates on Hoary Head, North West Nelson and on limestone substrates at its type locality in the Chalk Range, Marlborough.[3][2][12]

*Myosotis arnoldii* is likely to be an outcrossing species, with plants requiring a pollinating vector to achieve pollination and seed set.[11]

## Conservation status

*Myosotis arnoldii* is listed as At Risk – Naturally Uncommon with the qualifiers Data Poor (DP) and Range Restricted (RR) on the most recent assessment (2017–2018) under the [New Zealand Threatened Classification](/source/New_Zealand_Threat_Classification_System) system for plants.[1]

## References

1. ^ [***a***](#cite_ref-NZTCS_1-0) [***b***](#cite_ref-NZTCS_1-1) Lange, Peter J. de; Rolfe, Jeremy R.; Barkla, John W.; Courtney, Shannel P.; Champion, Paul D.; Perrie, Leon R.; Beadel, Sarah M.; Ford, Kerry A.; Breitwieser, Ilse; Schönberger, Ines; Hindmarsh-Walls, Rowan (May 2018). ["Conservation status of New Zealand indigenous vascular plants, 2017"](https://www.doc.govt.nz/globalassets/documents/science-and-technical/nztcs22entire.pdf) (PDF). *New Zealand Threat Classification Series*. **22**: 45. [OCLC](/source/OCLC_(identifier)) [1041649797](https://search.worldcat.org/oclc/1041649797).

1. ^ [***a***](#cite_ref-:2_2-0) [***b***](#cite_ref-:2_2-1) [***c***](#cite_ref-:2_2-2) [***d***](#cite_ref-:2_2-3) [***e***](#cite_ref-:2_2-4) [***f***](#cite_ref-:2_2-5) [***g***](#cite_ref-:2_2-6) Moore, L.B. ["Boraginaceae. In 'Flora of New Zealand'. (Ed. HH Allan) Vol. 1, pp. 806–833"](https://floraseries.landcareresearch.co.nz/pages/Taxon.aspx?id=_2dd90ab4-331f-4d49-bb31-b0a843e65931&fileName=Flora%201.xml). *(Government Printer: Wellington, New Zealand) floraseries.landcareresearch.co.nz*. Retrieved 27 April 2022.

1. ^ [***a***](#cite_ref-:0_3-0) [***b***](#cite_ref-:0_3-1) [***c***](#cite_ref-:0_3-2) [***d***](#cite_ref-:0_3-3) [***e***](#cite_ref-:0_3-4) ["Myosotis arnoldii"](https://www.nzpcn.org.nz/flora/species/myosotis-arnoldii/). *New Zealand Plant Conservation Network*. Retrieved 26 July 2023.

1. **[^](#cite_ref-4)** ["Myosotis arnoldii isotype | Collections Online - Museum of New Zealand Te Papa Tongarewa"](https://collections.tepapa.govt.nz/object/664561). *collections.tepapa.govt.nz*. Retrieved 26 July 2023.

1. **[^](#cite_ref-5)** ["Myosotis arnoldii isotype | Collections Online - Museum of New Zealand Te Papa Tongarewa"](https://collections.tepapa.govt.nz/object/696411). *collections.tepapa.govt.nz*. Retrieved 27 July 2023.

1. **[^](#cite_ref-:13_6-0)** Meudt, Heidi (2021). ["Taxonomic revision of five species groups of ebracteate-erect Myosotis (Boraginaceae) endemic to New Zealand, based on morphology, and description of new subspecies"](https://www.publish.csiro.au/SB/SB20028). *Australian Systematic Botany*. **34** (3): 252–304. [doi](/source/Doi_(identifier)):[10.1071/SB20028](https://doi.org/10.1071%2FSB20028). [S2CID](/source/S2CID_(identifier)) [234771910](https://api.semanticscholar.org/CorpusID:234771910).

1. ^ [***a***](#cite_ref-:12_7-0) [***b***](#cite_ref-:12_7-1) Meudt, Heidi M.; Prebble, Jessica M.; Lehnebach, Carlos A. (1 May 2015). ["Native New Zealand forget-me-nots (Myosotis, Boraginaceae) comprise a Pleistocene species radiation with very low genetic divergence"](https://doi.org/10.1007/s00606-014-1166-x). *Plant Systematics and Evolution*. **301** (5): 1455–1471. [doi](/source/Doi_(identifier)):[10.1007/s00606-014-1166-x](https://doi.org/10.1007%2Fs00606-014-1166-x). [ISSN](/source/ISSN_(identifier)) [2199-6881](https://search.worldcat.org/issn/2199-6881). [S2CID](/source/S2CID_(identifier)) [254048318](https://api.semanticscholar.org/CorpusID:254048318).

1. ^ [***a***](#cite_ref-:32_8-0) [***b***](#cite_ref-:32_8-1) Winkworth, Richard C; Grau, Jürke; Robertson, Alastair W; Lockhart, Peter J (1 August 2002). ["The origins and evolution of the genus Myosotis L. (Boraginaceae)"](https://www.sciencedirect.com/science/article/pii/S1055790302002105). *Molecular Phylogenetics and Evolution*. **24** (2): 180–193. [doi](/source/Doi_(identifier)):[10.1016/S1055-7903(02)00210-5](https://doi.org/10.1016%2FS1055-7903%2802%2900210-5). [ISSN](/source/ISSN_(identifier)) [1055-7903](https://search.worldcat.org/issn/1055-7903). [PMID](/source/PMID_(identifier)) [12144755](https://pubmed.ncbi.nlm.nih.gov/12144755).

1. **[^](#cite_ref-9)** Prebble, Jessica; Tate, Jennifer Alane; Meudt, Heidi; Symonds, Vaughan (9 June 2015). ["Microsatellite markers for the New Zealand endemic Myosotis pygmaea species group (Boraginaceae) amplify across species"](https://bsapubs.onlinelibrary.wiley.com/doi/full/10.3732/apps.1500027). *Applications in Plant Sciences*. **3** (6). [doi](/source/Doi_(identifier)):[10.3732/APPS.1500027](https://doi.org/10.3732%2FAPPS.1500027). [PMC](/source/PMC_(identifier)) [4467761](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4467761). [PMID](/source/PMID_(identifier)) [26082880](https://pubmed.ncbi.nlm.nih.gov/26082880).

1. ^ [***a***](#cite_ref-:02_10-0) [***b***](#cite_ref-:02_10-1) Prebble, Jessica; Meudt, Heidi; Tate, Jennifer Alane; Symonds, Vaughan (1 August 2019). ["Comparing and co‐analysing microsatellite and morphological data for species delimitation in the New Zealand native Myosotis pygmaea species group (Boraginaceae)"](https://onlinelibrary.wiley.com/doi/10.1002/tax.12096). *Taxon*. **68** (4): 731–750. [doi](/source/Doi_(identifier)):[10.1002/TAX.12096](https://doi.org/10.1002%2FTAX.12096).

1. ^ [***a***](#cite_ref-:1_11-0) [***b***](#cite_ref-:1_11-1) Mary Brandon, Andrea (2001). [*Breeding systems and rarity in New Zealand Myosotis*](http://hdl.handle.net/10179/2146) (PhD thesis). [Massey University](/source/Massey_University).

1. **[^](#cite_ref-12)** ["Calcareous cliffs, scarps and tors"](https://www.landcareresearch.co.nz/publications/naturally-uncommon-ecosystems/inland-and-alpine/calcareous-cliffs-scarps-and-tors/). *Manaaki Whenua*. Retrieved 26 July 2023.

## External links

Wikimedia Commons has media related to [Myosotis arnoldii](https://commons.wikimedia.org/wiki/Category:Myosotis_arnoldii).

- [*Myosotis arnoldii* occurrence data from Australasian Virtual Herbarium](https://avh.ala.org.au/occurrences/search?taxa=myosotis+arnoldii#tab_mapView)

Taxon identifiers Myosotis arnoldii Wikidata: Q17416594 Wikispecies: Myosotis arnoldii CoL: 455T4 GBIF: 5661582 iNaturalist: 404026 IPNI: 118910-1 NZOR: 4f54354f-4f0e-41c8-8f65-f205e73d2674 NZPCN: 590 Open Tree of Life: 6062869 POWO: urn:lsid:ipni.org:names:118910-1 WFO: wfo-0000367844

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Adapted from the Wikipedia article [Myosotis arnoldii](https://en.wikipedia.org/wiki/Myosotis_arnoldii) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Myosotis_arnoldii?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.