{{Short description|Species of flowering plant}} {{Use New Zealand English|date=July 2024}} {{Use dmy dates|date=January 2020}} {{Speciesbox | image = SP107316 Myosotis laeta Cheeseman WELT Te Papa 1759281 511193.jpg | image_caption = | status = NE | status_system = NZTCS | status_ref = <ref name="NZTCS"/> | genus = Myosotis | species = laeta | authority = [[Thomas Cheeseman|Cheeseman]], 1885<ref name="Cheeseman">{{cite Q|Q115527957|page=236}}</ref> }}

'''''Myosotis laeta''''' is a species of [[flowering plant]] in the [[Family (taxonomy)|family]] Boraginaceae, [[Endemic species|endemic]] to [[Ultramafic rock|ultramafic]] areas of the Sounds-Nelson area of the [[South Island]] of [[New Zealand]]. [[Thomas Cheeseman]] described the species in 1885. Plants of this species of [[Forget-me-nots|forget-me-not]] are [[Perennial plant|perennial]] rosettes which form loose tufts or clumps, with ebracteate, erect inflorescences, and white corollas.

== Taxonomy and etymology == [[File:Myosotis laeta (Cheeseman, 1885) (AM AK7531).jpg|thumb|left|Specimen of ''Myosotis laeta'' collected by [[Thomas Cheeseman]]]]

''Myosotis laeta'' is in the plant family [[Boraginaceae]] and was described in 1885 by [[Thomas Cheeseman]].<ref name=":2">{{Cite web |last=Moore |first=L.B. |title=Boraginaceae. In 'Flora of New Zealand'. (Ed. HH Allan) Vol. 1, pp. 806–833 |url=https://floraseries.landcareresearch.co.nz/pages/Taxon.aspx?id=_2dd90ab4-331f-4d49-bb31-b0a843e65931&fileName=Flora%201.xml |access-date=2022-04-27 |website=(Government Printer: Wellington, New Zealand) floraseries.landcareresearch.co.nz}}</ref><ref name=":1" /><ref name="Cheeseman"/><ref>{{Cite web |title=Myosotis laeta |url=https://www.nzpcn.org.nz/flora/species/myosotis-laeta/ |access-date=2022-08-26 |website=New Zealand Plant Conservation Network |language=en}}</ref>

''Myosotis laeta'' is morphologically similar to other ebracteate-erect species, especially ''M. brockiei'', ''M. capitata'' and ''M. rakiura''.<ref name=":1" /> It is probably most similar to ''M. brockiei'' from Western Nelson, South Island, New Zealand. ''M. laeta'' is also sometimes confused with ''M. monroi'', whose geographic range overlaps with that of ''M. laeta'' in [[Ultramafic rock|ultramafic]] areas of Sounds-Nelson, South Island.<ref name=":1" />

''Myosotis laeta'' can be distinguished from ''[[Myosotis brockiei|M. brockiei]]'' by the following characters: the underside of the rosette leaves are much less hairy and are all retrorse (backward-facing), the hairs on the leaf edges are patent instead of erect, the calyx has hooked hairs, and the flower has short filaments. Some of these characters also help distinguish ''M. laeta'' from ''[[Myosotis rakiura|M. rakiura]]'' and ''[[Myosotis capitata|M. capitata]]'', both of which are found much further south in southern South Island and [[Rakiura (island)|Rakiura / Stewart Island]], and the [[New Zealand Subantarctic Islands|New Zealand subantarctic islands]], respectively.<ref name=":1">{{Cite Q |last=Meudt |first=Heidi |date=2021 |title=Taxonomic revision of five species groups of ebracteate-erect Myosotis (Boraginaceae) endemic to New Zealand, based on morphology, and description of new subspecies |Q107671092}}</ref>

''Myosotis laeta'' can be distinguished from ''M. monroi'' by its patent, oblique, flexuous hairs on the leaf that are retrorse on the underside, its unbranched inflorescences, the retrorse hairs on the smaller calyx, and its calyx lobes that are more than half the length of the calyx.<ref name=":1" />

The lectotype specimen of ''Myosotis laeta'' was collected by Thomas Cheeseman from Red Hills, Wairau in 1882 and is lodged at the [[Auckland War Memorial Museum]] Herbarium (AK 7531).<ref name=":1" /><ref>{{Cite web |title=Lectotype of Myosotis laeta |url=https://www.aucklandmuseum.com/collections-research/collections/record/am_naturalsciences-object-426566 |access-date=2022-08-26 |publisher=[[Auckland War Memorial Museum]]}}</ref> There is also an isolectotype there (AK 210594)<ref>{{Cite web |title=Isolectotype of Myosotis laeta |url=https://www.aucklandmuseum.com/collections-research/collections/record/am_naturalsciences-object-361162 |access-date=2022-08-26 |publisher=[[Auckland War Memorial Museum]]}}</ref> and another at the [[Museum of New Zealand Te Papa Tongarewa]] (WELT SP002415).<ref name=":1" />

The [[specific epithet]], ''laeta'', is derived from the Latin ''laetus'' and means bright, cheerful or pleasant.<ref name=":1" />

== Phylogeny == ''Myosotis laeta'' has not yet been included in any [[Phylogenetics|phylogenetic]] analyses of southern hemisphere ''Myosotis'' using standard DNA sequencing markers ([[Ribosomal DNA|nuclear ribosomal DNA]] and [[chloroplast DNA]] regions).<ref name=":0">{{Cite journal |last1=Meudt |first1=Heidi M. |last2=Prebble |first2=Jessica M. |last3=Lehnebach |first3=Carlos A. |date=2015-05-01 |title=Native New Zealand forget-me-nots (Myosotis, Boraginaceae) comprise a Pleistocene species radiation with very low genetic divergence |journal=Plant Systematics and Evolution |language=en |volume=301 |issue=5 |pages=1455–1471 |doi=10.1007/s00606-014-1166-x |bibcode=2015PSyEv.301.1455M |s2cid=254048318 |issn=2199-6881}}</ref><ref>{{Cite Q|Q30707919}}</ref>

<gallery mode="packed" heights="170"> File:SP107316 Myosotis laeta Cheeseman WELT Te Papa 1759281 511242.jpg|Rosettes File:SP105625_Myosotis_laeta_Cheeseman_WELT_Te_Papa_1592453_400341.jpg|Inflorescence File:SP107316 Myosotis laeta Cheeseman WELT Te Papa 1759281 511215.jpg|Leaves </gallery>

== Description == ''Myosotis laeta'' plants are single rosettes that often grow together to form loose tufts or clumps. The rosette leaves have [[Petiole (botany)|petioles]] 4–29&nbsp;mm long. The rosette leaf blades are 8–35&nbsp;mm long by 4–10&nbsp;mm wide (length: width ratio 1.5–4.0: 1), narrowly obovate or oblanceolate, widest at or above the middle, with an [[Obtuse (leaf)|obtuse]] apex. The upper surface and the edges of the leaf are densely covered in mostly flexuous, patent to erect, antrorse (forward-facing) hairs that are usually oriented oblique to the mid vein. The hairs on the underside of the leaf are similar but mostly retrorse (backward-facing), oriented parallel or oblique to the mid vein, and less hairy (sparsely to densely distributed). Each rosette has 1–2 erect, unbranched, ebracteate [[inflorescence]]s that are up to 220&nbsp;mm long. The cauline leaves are similar to the rosette leaves but smaller with shorter petioles, and decrease in size toward the tip. Each inflorescence has up to 15 flowers, each borne on a [[Pedicel (botany)|pedicel]] up to 4&nbsp;mm long at fruiting, and each without a bract. The calyx is 3–5&nbsp;mm long at flowering or fruiting, lobed to half to nearly its full length, and densely covered in mostly antrorse (some retrorse near the base), appressed to patent hairs, that can be straight, flexuous, curved, or hooked. The corolla is white, up to 11&nbsp;mm in diameter, with a cylindrical tube, petals that are broadly ovate or broadly obovate, and small yellow scales alternating with the petals. The anthers are fully exserted above the scales. The four smooth, shiny, light brown nutlets are 1.4–2.1&nbsp;mm long by 0.6–1.2&nbsp;mm wide and narrowly ovoid in shape.<ref name=":1" />

The chromosome number of ''M. laeta'' is unknown.

The pollen of ''M. laeta'' is unknown.

It flowers and fruits from November–January, with the main flowering and fruiting period in January.<ref name=":1" />

== Distribution and habitat == ''Myosotis laeta'' is a [[forget-me-not]] endemic to the Richmond Range, Sounds-Nelson, northern South Island of New Zealand from 850–1200 m ASL. It is found in damp ultramafic grassland, shrubland or fellfield in the mineral belt.<ref name=":1" />

== Conservation status == The species is listed as Threatened - Nationally Endangered on the most recent assessment (2017-2018) under the [[New Zealand Threat Classification System|New Zealand Threatened Classification]] system for plants, with the qualifiers "DP" (Data Poor), "RR" (Range Restricted), "RF" Recruitment Failure, and "St" (Stable).<ref name="NZTCS">{{Cite journal |last1=Lange |first1=Peter J. de |last2=Rolfe |first2=Jeremy R. |last3=Barkla |first3=John W. |last4=Courtney |first4=Shannel P. |last5=Champion |first5=Paul D. |last6=Perrie |first6=Leon R. |last7=Beadel |first7=Sarah M. |last8=Ford |first8=Kerry A. |last9=Breitwieser |first9=Ilse |last10=Schönberger |first10=Ines |last11=Hindmarsh-Walls |first11=Rowan |date=May 2018 |title=Conservation status of New Zealand indigenous vascular plants, 2017 |url=https://www.doc.govt.nz/globalassets/documents/science-and-technical/nztcs22entire.pdf |journal=New Zealand Threat Classification Series |volume=22 |pages=45 |oclc=1041649797}}</ref><ref name=":1" />

== References == {{Reflist|refs=}}

== External links == * [https://avh.ala.org.au/occurrences/search?taxa=myosotis+laeta#tab_mapView ''Myosotis laeta'' occurrence data from Australasian Virtual Herbarium]

{{Taxonbar|from=Q17416540}}

[[Category:Myosotis|laeta]] [[Category:Endemic flora of New Zealand]] [[Category:Endangered flora of New Zealand]] [[Category:Taxa named by Thomas Frederic Cheeseman]] [[Category:Plants described in 1885]]