# Myosotis exarrhena

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Species of flowering plant

Myosotis exarrhena Conservation status Least Concern (IUCN 3.1) Scientific classification Kingdom: Plantae Clade: Embryophytes Clade: Tracheophytes Clade: Spermatophytes Clade: Angiosperms Clade: Eudicots Clade: Asterids Order: Boraginales Family: Boraginaceae Genus: Myosotis Species: M. exarrhena Binomial name Myosotis exarrhena F.Muell[1] Synonyms Exarrhena suaveolens R.Br.

***Myosotis exarrhena*** is a species of [flowering plant](/source/Flowering_plant) in the [family](/source/Family_(taxonomy)) [Boraginaceae](/source/Boraginaceae), [endemic](/source/Endemic_species) to Australia. [Robert Brown](/source/Robert_Brown_(botanist%2C_born_1773)) described this species as *Exarrhena suaveolens* in 1810. Plants of this species of [forget-me-not](/source/Forget-me-nots) are [perennial](/source/Perennial_plant) rosettes with ebracteate inflorescences and white corollas with exserted stamens.

## Taxonomy and etymology

*Myosotis exarrhena* [F.Muell.](/source/Ferdinand_von_Mueller) is in the plant family [Boraginaceae](/source/Boraginaceae). The species was originally described by [Robert Brown](/source/Robert_Brown_(botanist%2C_born_1773)) in his *[Prodromus](/source/Prodromus_Florae_Novae_Hollandiae_et_Insulae_Van_Diemen)* in 1810 as *Exarrhena suaveolens* R.Br.[2] It was transferred to the genus *Myosotis* as *M. suaveolens* (R.Br.) Poir. in 1816, but this was an illegitimate name owing to *M. suaveolens* [Waldst.](/source/Waldst.) & [Kit.](/source/Kit.) ex [Willd.](/source/Willd.), which was published in 1809 based on a European type.[3]*[4]* [Ferdinand von Mueller](/source/Ferdinand_von_Mueller) finally made the valid combination *M. exarrhena* in 1889 in the updated *[Systematic Census of Australian Plants](/source/Systematic_Census_of_Australian_Plants).*[1]

Habit and flowers of Myosotis exarrhena observed in Victoria, Australia

The lectotype (K001094009) and the isolectotype (K001094010) of *Exarrhena* *suaveolens* are on the same sheet at [Kew Herbarium](/source/Kew_Herbarium),[5] and were designated by Peter G. Wilson & Jeannie Highet.*[4]*

*Myosotis exarrhena* is one of two species native to Australia.[3] *[Myosotis australis](/source/Myosotis_australis)* is native to Australia, as well as New Zealand and New Guinea*.[3] Myosotis exarrhena* is morphologically more similar to other ebracteate-erect species from New Zealand, especially *Myosotis concinna,*[6] than to *M. australis.*[3] The Australian *M. exarrhena* can be distinguished from the New Zealand *M. concinna* by its white corollas, retrorse hairs on the underside of the rosette leaves and scape, and lack of hooked hairs on the calyx.[6]

The species epithet *exarrhena* is based on the Greek word *arrhen* and refers to the exerted anthers.[3]

## Phylogeny

One individual of *Myosotis exarrhena* was included in [phylogenetic](/source/Phylogenetics) analyses of standard DNA sequencing markers ([nuclear ribosomal DNA](/source/Ribosomal_DNA) and [chloroplast DNA](/source/Chloroplast_DNA) regions).[7][8]

Inflorescences with flowers

Within the southern hemisphere lineage, species relationships were not well resolved.[7][8] The individual of *M. exarrhena* grouped with Australian *M. australis* and several other mostly ebracteate-erect New Zealand *Myosotis* species*.[7][8]*

## Description

***Myosotis exarrhena*** plants are rosettes that are often stoloniferous. The rosette leaves have [petioles](/source/Petiole_(botany)) that are 6–30 mm long. The rosette leaf blades are 7–55 mm long by 2–10 mm wide (length: width ratio 1.0–7.6: 1), lanceolate, oblanceolate or narrowly oblanceolate, widest below, at or above the middle, usually with an [obtuse](/source/Glossary_of_leaf_morphology#obtuse) apex. Both surfaces of the leaf are uniformly and densely covered in flexuous to curved, usually appressed, antrorse (forward-facing) hairs that are oriented parallel to the midrib**.** Each rosette has multiple ascending**,** branched ebracteate [inflorescences](/source/Inflorescence) that are bifurcating at the top and up to 470 mm long. The cauline leaves are similar to the rosette leaves, but become smaller. The flowers are 36–91 per inflorescence and each is borne on a short [pedicel](/source/Pedicel_(botany)) without a bract. The calyx is 2–5 mm long at flowering and 3–6 mm long at fruiting, lobed to half to two-thirds of its length, and densely covered in straight to flexuous, often hooked, patent to erect, mostly antrorse hairs (with some retrorse or backward-facing hairs near the base). The corolla is white and 5–11 mm in diameter, with a cylindrical tube, petals that are usually narrowly ovate or ovate, and small yellow scales alternating with the petals. The anthers are fully exserted. The four smooth, shiny, usually medium to dark brown nutlets are 1.7–2.3 mm long by 1.0–1.5 mm wide and usually ovoid in shape.[3]

The pollen of *Myosotis exarrhena* is of the *exarrhena* type.[3]

The chromosome number of *M. exarrhena* is unknown.[3]

Flowering and fruiting between October–March, with the main flowering period from December–February.[3]

## Distribution and habitat

*Myosotis exarrhena* is endemic to Australia in the states of New South Wales, Australian Capital Territory, Victoria and Tasmania from 555 to 1000 m ASL, possibly up to 1370 m ASL, in forest, woodland, clearings or stream banks, on slopes, outcrops or banks.[3]

## Conservation status

*Myosotis exarrhena* is not listed on the Australian Government's EPBC Act list of Threatened Flora.[9] It is likely to be considered to be LC (Least Concern) according to the IUCN.[3]

## Hybridisation

On the basis of morphological data, *Myosotis exarrhena* may hybridise with *M. australis* where the two species are known to co-occur in New South Wales, ACT and Victoria.[3] Several specimens have been identified as interspecific *M. exarrhena* × *M. australis* hybrids.[3]

## References

1. ^ [***a***](#cite_ref-Mueller_1-0) [***b***](#cite_ref-Mueller_1-1) [Ferdinand von Mueller](/source/Ferdinand_von_Mueller) (1889), *Second systematic census of Australian plants, with chronologic, literary and geographic annotations;*, Melbourne: Printed for the Victorian Government by McCarron. Bird & Co., [doi](/source/Doi_(identifier)):[10.5962/BHL.TITLE.23173](https://doi.org/10.5962%2FBHL.TITLE.23173), [OCLC](/source/OCLC_(identifier)) [5873715](https://search.worldcat.org/oclc/5873715), [OL](/source/OL_(identifier)) [7024831M](https://openlibrary.org/books/OL7024831M), [Wikidata](/source/WDQ_(identifier)) [Q51433898](https://www.wikidata.org/wiki/Q51433898)

1. **[^](#cite_ref-2)** [Brown, Robert, 1773-1858](/source/Robert_Brown_(botanist%2C_born_1773)) (1810), *Prodromus florae Novae Hollandiae et Insulae Van-Diemen, exhibens characteres plantarum* (in Latin), London: Typis R Taylor, veneunt apud J. Johnson, [doi](/source/Doi_(identifier)):[10.5962/BHL.TITLE.6720](https://doi.org/10.5962%2FBHL.TITLE.6720), [OCLC](/source/OCLC_(identifier)) [9885199](https://search.worldcat.org/oclc/9885199), [OL](/source/OL_(identifier)) [13508332M](https://openlibrary.org/books/OL13508332M), [Wikidata](/source/WDQ_(identifier)) [Q51522645](https://www.wikidata.org/wiki/Q51522645){{[citation](https://en.wikipedia.org/wiki/Template:Citation)}}: CS1 maint: multiple names: authors list ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_multiple_names:_authors_list)) CS1 maint: numeric names: authors list ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_numeric_names:_authors_list))

1. ^ [***a***](#cite_ref-:5_3-0) [***b***](#cite_ref-:5_3-1) [***c***](#cite_ref-:5_3-2) [***d***](#cite_ref-:5_3-3) [***e***](#cite_ref-:5_3-4) [***f***](#cite_ref-:5_3-5) [***g***](#cite_ref-:5_3-6) [***h***](#cite_ref-:5_3-7) [***i***](#cite_ref-:5_3-8) [***j***](#cite_ref-:5_3-9) [***k***](#cite_ref-:5_3-10) [***l***](#cite_ref-:5_3-11) [***m***](#cite_ref-:5_3-12) Heidi M. Meudt; Michael J. Thorsen; Jessica Prebble (2020). "Taxonomic revision of the Myosotis australis group (Boraginaceae) native to Australia, New Zealand and New Guinea". *[Australian Systematic Botany](/source/Australian_Systematic_Botany)*. **33** (6): 477. [doi](/source/Doi_(identifier)):[10.1071/SB20014](https://doi.org/10.1071%2FSB20014). [ISSN](/source/ISSN_(identifier)) [1030-1887](https://search.worldcat.org/issn/1030-1887). [Wikidata](/source/WDQ_(identifier)) [Q107670735](https://www.wikidata.org/wiki/Q107670735).

1. ^ [***a***](#cite_ref-:6_4-0) [***b***](#cite_ref-:6_4-1) Peter G. Wilson; Jeannie Highet (1988). "Myosotis exarrhena F.Muell., the correct namefor M. suaveolens (R.Br.) Poir. (Boraginaceae)". *[Telopea](/source/Telopea_(journal))*. **3**: 283–284. [doi](/source/Doi_(identifier)):[10.7751/TELOPEA19884815](https://doi.org/10.7751%2FTELOPEA19884815). [ISSN](/source/ISSN_(identifier)) [0312-9764](https://search.worldcat.org/issn/0312-9764). [Wikidata](/source/WDQ_(identifier)) [Q118358923](https://www.wikidata.org/wiki/Q118358923).

1. **[^](#cite_ref-5)** ["Lectotype and isolectotype of Myosotis exarrhena on JSTOR"](https://plants.jstor.org/stable/10.5555/al.ap.specimen.k001094010). *plants.jstor.org*. Retrieved 14 May 2023.

1. ^ [***a***](#cite_ref-:7_6-0) [***b***](#cite_ref-:7_6-1) Heidi M. Meudt (2021). "Taxonomic revision of five species groups of ebracteate-erect Myosotis (Boraginaceae) endemic to New Zealand, based on morphology, and description of new subspecies". *[Australian Systematic Botany](/source/Australian_Systematic_Botany)*. **34** (3): 252–304. [doi](/source/Doi_(identifier)):[10.1071/SB20028](https://doi.org/10.1071%2FSB20028). [ISSN](/source/ISSN_(identifier)) [1030-1887](https://search.worldcat.org/issn/1030-1887). [Wikidata](/source/WDQ_(identifier)) [Q107671092](https://www.wikidata.org/wiki/Q107671092).

1. ^ [***a***](#cite_ref-:1_7-0) [***b***](#cite_ref-:1_7-1) [***c***](#cite_ref-:1_7-2) 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).

1. ^ [***a***](#cite_ref-:0_8-0) [***b***](#cite_ref-:0_8-1) [***c***](#cite_ref-:0_8-2) Richard Winkworth; Jürke Grau; Alastair W. Robertson; Peter Lockhart (1 August 2002). "The origins and evolution of the genus Myosotis L. (Boraginaceae)". *[Molecular Phylogenetics and Evolution](/source/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). [Wikidata](/source/WDQ_(identifier)) [Q30707919](https://www.wikidata.org/wiki/Q30707919).

1. **[^](#cite_ref-9)** ["EPBC Act List of Threatened Flora"](http://www.environment.gov.au/cgi-bin/sprat/public/publicthreatenedlist.pl?wanted=flora#flora_critically_endangered). *Species Profile and Threats Database*. Retrieved 15 May 2023.

## External links

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

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

Taxon identifiers Myosotis exarrhena Wikidata: Q17416562 Wikispecies: Myosotis exarrhena APNI: 107352 CoL: 455VX EPPO: MYOSU GBIF: 5661320 iNaturalist: 513771 IPNI: 150544-3 NCBI: 192350 NSWFlora: Myosotis~exarrhena Open Tree of Life: 236653 Plant List: kew-2358269 POWO: urn:lsid:ipni.org:names:150544-3 VicFlora: 0b25f113-76ce-4ef5-aecb-be8bd77723e8 WFO: wfo-0000367985

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