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Myosotis capitata

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Myosotis capitata
Plate XXXVII of Hooker's Flora Antarctica

Naturally Uncommon (NZ TCS)[1]
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Boraginales
Family: Boraginaceae
Genus: Myosotis
Species:
M. capitata
Binomial name
Myosotis capitata

Myosotis capitata is a species of flowering plant in the family Boraginaceae, endemic to the Campbell and Auckland Islands of New Zealand. Joseph Dalton Hooker described the species in his 19th century work Flora Antarctica. Plants of this species of forget-me-not are perennial and erect, and have ebracteate inflorescences and blue corollas. It is one of two native species of Myosotis in the New Zealand subantarctic islands, the other being M. antarctica, which can also have blue corollas.

Taxonomy and etymology

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Myosotis capitata Hook.f. is in the plant family Boraginaceae and was described in 1844 by Joseph Dalton Hooker.[3][4][5] After its description, Hooker expanded the circumscription of M. capitata to include plants from Rakiura / Stewart Island, New Zealand.[5][6] Joseph Beattie Armstrong described a new variety, M. capitata var. albiflora J.B.Armstr., for the Stewart Island plants and other similar fleshy, white-flowered plants from southern South Island, New Zealand, for which the name M. rakiura L.B.Moore is now used.[7][8] Myosotis capitata can be distinguished from M. rakiura in its blue corollas, lack of retrorse trichomes anywhere on the plant, including the underside of the leaves, and partially exserted anthers.[9] The type specimen of Myosotis capitata is lodged at Kew Herbarium.[9][10]

The specific epithet, capitata, derives from the Latin, caput/capitis, meaning "head" and hence describes the plant as having its flowers arranged in tightly compacted, head-like inflorescences.[11]

Phylogeny

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Myosotis capitata was shown to be a part of the monophyletic southern hemisphere lineage of Myosotis in phylogenetic analyses of standard DNA sequencing markers (nuclear ribosomal DNA and chloroplast DNA regions).[12][13] Within the southern hemisphere lineage, species relationships were not well resolved.[12][13] The sequences of M. capitata are not that similar to the other native subantarctic species, M. antarctica, and the sole individual of M. capitata sampled formed a unique lineage in the chloroplast DNA network.[13]

Description

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Myosotis capitata plants are small rosettes that may cluster together into tufts or loose clumps. The rosette leaves have petioles 8–25 mm long. The rosette leaf blades are 13–48 mm long by 4–19 mm wide (length: width ratio 1.5–4.2: 1), elliptic, oblanceolate or narrowly obovate, widest at or above the middle, with an obtuse apex. The upper surface of the leaf is densely covered in long silky forward-facing hairs, while on the lower surface the hairs are shorter, fewer and also forward-facing. Each rosette has 2–7 ascending to erect, branched, ebracteate inflorescences that are up to 37 cm long. The cauline leaves on the lower part of the inflorescence are similar to the rosette leaves, and decrease in size toward the tip. There can be up to 150 flowers condensed near the top of each inflorescence. Although the flowers are borne on short pedicels, they do not have bracts. The calyx is 2–4 mm long at flowering and 4–6 mm long at fruiting, lobed to half or more of its length, and densely covered in long, forward-facing silky hairs. The corolla is deep blue, up to 10 mm in diameter, with a cylindrical tube, petals that are rounded and flat, and small yellow scales alternating with the petals. The anthers are partly exserted, with the tips only surpassing the scales. The four smooth, shiny, black nutlets are 1.4–2.1 mm long by 1.0–1.7 mm wide and ovoid in shape.[9]

The chromosome number of M. capitata is 2n = 46.[14]

It flowers and fruits from November to February.[9]

Distribution and habitat

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Myosotis capitata is a forget-me-not endemic to the Auckland Islands and Campbell Island, New Zealand. On the Auckland Islands, it has been collected on Auckland Island, Adams Island and Ewing Island.[9][15][16] It is found from sea level up to altitudes of 630m, on the shore edge, rocks, bluffs or cliffs in exposed fellfield or banks with sparse vegetation.[4][9]

Conservation status

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The species is listed as "At Risk - Naturally Uncommon" on the most recent assessment (2017-2018) under the New Zealand Threatened Classification system for plants, because of its range which is restricted to certain subantarctic islands.[1][9]

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References

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  1. ^ a b 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" (PDF). New Zealand Threat Classification Series. 22: 45. OCLC 1041649797.
  2. ^ Hooker, J.D. (1844) The botany of the Antarctic voyage of H.M. discovery ships Erebus and Terror in the Years 1839-1843 :under the command of Captain Sir James Clark Ross: 1: 56
  3. ^ Moore, L.B. "Boraginaceae. In 'Flora of New Zealand'. (Ed. HH Allan) Vol. 1, pp. 806–833". (Government Printer: Wellington, New Zealand) floraseries.landcareresearch.co.nz. Retrieved 27 April 2022.
  4. ^ a b "Myosotis capitata | New Zealand Plant Conservation Network". nzpcn.org.nz. Retrieved 23 November 2019.
  5. ^ a b Hooker JD (1853) ‘The Botany of the Antarctic Voyage. II. Flora Novae-Zelandiae.’ (Reeve: London, UK)
  6. ^ Hooker JD (1864) ‘Handbook of the New Zealand Flora. Part I.’ (Reeve:London, UK)
  7. ^ Armstrong JB (1881) Descriptions of new and rare New Zealand plants. Transactions and Proceedings of the New Zealand Institute 13, 335–343.
  8. ^ Moore LB (1961) Boraginaceae. In ‘Flora of New Zealand’. (Ed. HH Allan) Vol. 1, pp. 806–833. (Government Printer: Wellington, New Zealand)
  9. ^ a b c d e f g Meudt, Heidi M. (30 April 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. 34 (3): 252–304. doi:10.1071/SB20028. ISSN 1446-5701. S2CID 234771910.
  10. ^ "Myosotis capitata Hook.f." apps.kew.org. 2022. Retrieved 25 April 2022.
  11. ^ "capitatus,-a,-um". www.plantillustrations.org. Retrieved 11 January 2020.
  12. ^ a b Winkworth, Richard C; Grau, Jürke; Robertson, Alastair W; Lockhart, Peter J (1 August 2002). "The origins and evolution of the genus Myosotis L. (Boraginaceae)". Molecular Phylogenetics and Evolution. 24 (2): 180–193. doi:10.1016/S1055-7903(02)00210-5. ISSN 1055-7903. PMID 12144755.
  13. ^ a b c 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". Plant Systematics and Evolution. 301 (5): 1455–1471. doi:10.1007/s00606-014-1166-x. ISSN 2199-6881. S2CID 254048318.
  14. ^ Beuzenberg, EJ; Hair, J (1983). "Contributions to a chromosome atlas of the New Zealand flora - 25 miscellaneous species". New Zealand Journal of Botany. 21: 13–20. doi:10.1080/0028825X.1983.10428520 (inactive 1 November 2024).{{cite journal}}: CS1 maint: DOI inactive as of November 2024 (link)
  15. ^ "What happens when you ask ornithologists to do botany". Te Papa’s Blog. 6 March 2018. Retrieved 25 April 2022.
  16. ^ "Australasian Virtual Herbarium". avh.ala.org.au. Retrieved 26 April 2022.
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