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Myosotis antarctica subsp. antarctica

Myosotis antarctica subsp. antarctica is a subspecies of flowering plant in the family Boraginaceae, native to New Zealand, Campbell Island, and southern Chile. Joseph Dalton Hooker described the species in his 19th century work Flora Antarctica. Plants of this subspecies of forget-me-not are perennial with a prostrate habit, bracteate inflorescences, and white or blue corollas. It is one of two native Myosotis in the New Zealand subantarctic islands, the other being M. capitata, which also has blue corollas.

Myosotis antarctica subsp. 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. antarctica
Subspecies:
M. a. subsp. antarctica
Trinomial name
Myosotis antarctica subsp. antarctica
Synonyms

Taxonomy and etymology

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Myosotis antarctica Hook.f. subsp antarctica is in the family Boraginaceae. Myosotis antarctica was described in 1844 by Joseph Dalton Hooker from the New Zealand subantarctic islands.[3][2][4] Botanists' circumscription of Myosotis antarctica has changed over time[5], sometimes referring only to plants from Campbell Island and Chile.[4], or also including plants from mainland New Zealand.

The latest taxonomic revision of recognizes an expanded M. antarctica which includes plants from mainland New Zealand, Campbell Island and Chile, including those previously called M. drucei and M. pygmaea.[5][6] The two allopatric subspecies of M. antarctica are M. antarctica subsp. antarctica (previously M. antarctica from Campbell Island and Chile, and M. drucei from mainland New Zealand) and M. antarctica subsp. traillii (previously M. pygmaea from mainland New Zealand).

Myosotis antarctica subsp. antarctica can be distinguished from M. antarctica subsp. traillii by its flexuous, spreading to erect hairs on the blade and edges of the rosette leaves. Plants of subsp. antarctica are usually found at inland localities on mainland New Zealand, but can be coastal in Fiordland, Campbell Island and Chile. By contrast, M. antarctica subsp. traillii has curved, appressed to spreading hairs on the blade and edges of the rosette leaves. Plants of subsp. traillii are usually found on coastal localities in mainland New Zealand.[5]

The type specimen of Myosotis antarctica was collected by Joseph Hooker on Campbell Island and is lodged at Kew Herbarium.[7]

The specific epithet, antarctica, derives from its presence on the New Zealand subantarctic islands.

Phylogeny

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Myosotis antarctica 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).[8][9] Within the southern hemisphere lineage, species relationships were not well resolved.[8][9] Sequences of both subspecies of M. antarctica (including some referred to as M. pygmaea and M. drucei) grouped with other New Zealand species that are morphologically similar, including M. brevis.[8]

Description

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Myosotis antarctica subsp. antarctica plants are single rosettes. The rosette leaves have petioles 1–20 mm long. The rosette leaf blades are 3–26 mm long by 1–11 mm wide (length: width ratio usually 1.0–4.0: 1), narrowly oblanceolate to very broadly obovate, widest at or above the middle, green or brown, with an obtuse apex. The upper surface of the leaf is densely covered in flexuous, patent to erect, evenly-distributed antrorse (forward-facing) hairs, whereas the lower surface of the leaf is similar but with fewer hairs (ranging from glabrous to with sparsely distributed hairs). The hairs on the leaf edges are spreading to erect. Each rosette has multiple prostrate, bracteate inflorescences that are usually up to 15 cm long (rarely up to 31 cm long). The cauline leaves are similar in size and shape to the rosette leaves and usually sessile. Each inflorescence has up to 46 flowers, each borne on a very short pedicel, with a bract. The calyx is 1–4 mm long at flowering and 2–7 mm long at fruiting, lobed to one-third to three-quarters its length, and hairs that are sometimes of two different lengths and types. The corolla is white, cream, or blue, up to 4 mm in diameter, with a cylindrical tube, and small yellow scales alternating with the petals. The anthers are very short (usually < 0.3 mm long) and fully included. The four smooth, shiny nutlets are usually 1.2–1.9 mm long by 0.8–1.2 mm wide and are ovoid in shape.[5]

The chromosome number of M. antarctica subsp. antarctica is n = 24 (CHR 101449, as Myosotis pygmaea s.l.)[10][11] or n = 22 (AK 331000, as M. aff. drucei).[12][13][5]

It flowers August–April and fruits September–April, with peak flowering and fruiting December–January.[5]

  •  
    Floral detail
  •  
    Close up of fruits
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    Growth habit
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    Pollen grain

Distribution and habitat

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Myosotis antarctica subsp. antarctica is a forget-me-not native to New Zealand, Campbell Island,[14] and southern Chile (Magallanes)[15] from 0–2200 m ASL.[5] Very few collections of this subspecies have been made from Chile, with the most recent being from "Punta Arenas" by Per Dusén in 1895 and from "Puerto Altamirano" by Carl Skottsberg in 1908.[5][16]

In mainland New Zealand, it is found in the following islands and ecological districts: North Island (Gisborne, Volcanic Plateau, Southern North Island), South Island (Western Nelson, Sounds-Nelson, Marlborough, Westland, Canterbury, Otago, Southland, Fiordland) and Stewart Island (Rakiura).[5] M. antarctica subsp. antarctica is found in habitats ranging from coastal to subalpine, including on turfs, fellfields, scree, and cliff faces.[5]

Conservation status

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The subspecies M. antarctica subsp. antarctica was previously listed as two different species in the most recent assessment (2017-2018) of the New Zealand Threatened Classification for plants. Thus, M. antarctica (=Campbell Island populations only) was listed as At Risk - Naturally Uncommon with qualifiers "DP" (Data Poor), "Sp" (Sparse) and "TO" (Threatened Overseas), whereas M. drucei (mainland New Zealand) was listed as Not Threatened.[1]

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: 1–86. OCLC 1041649797.
  2. ^ a b "Myosotis antarctica | New Zealand Plant Conservation Network". nzpcn.org.nz. Retrieved 23 November 2019.
  3. ^ a b 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: 57
  4. ^ a b 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.
  5. ^ a b c d e f g h i j Prebble, Jessica M.; Symonds, V. Vaughan; Tate, Jennifer A.; Meudt, Heidi M. (5 May 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. ISSN 1446-5701. S2CID 248603363.
  6. ^ "New names for some tiny forget-me-nots". Te Papa’s Blog. 8 June 2022. Retrieved 26 July 2022.
  7. ^ "Myosotis antarctica Hook.f." apps.kew.org. Retrieved 27 April 2022.
  8. ^ 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.
  9. ^ 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.
  10. ^ Hair, J. B.; Beuzenberg, E. J. (1968). "Contributions to a chromosome atlas of the New Zealand flora—11". New Zealand Journal of Botany. 6 (1): 19–24. doi:10.1080/0028825x.1968.10428786. ISSN 0028-825X.
  11. ^ "Myosotis pygmaea s.l." scd.landcareresearch.co.nz. Retrieved 11 August 2022.
  12. ^ Murray, BG; de Lange, PJ (2013). "Contributions to a chromosome atlas of the New Zealand flora – 40. Miscellaneous counts for 36 families". New Zealand Journal of Botany. 51 (1): 31–60. doi:10.1080/0028825x.2012.747969. ISSN 0028-825X. S2CID 85259182.
  13. ^ "Myosotis drucei". Auckland Museum.
  14. ^ Prebble, Jessie (8 January 2014). "Subantarctic forget-me-not adventures". Te Papa’s Blog. Retrieved 24 November 2019.
  15. ^ Zuloaga, Fernando O; Morrone, Osvaldo; Belgrano, Manuel J. (2008). Catálogo de las plantas vasculares del Cono Sur : (Argentina, Sur de Brasil, Chile, Paraguay y Uruguay). St. Louis, Mo.: Missouri Botanical Garden Press, Instituto de Botánica Darwinion. ISBN 978-1-930723-70-2. OCLC 294820637.
  16. ^ Skottsberg, C (1941). "Communities of marine algae in Subantarctic and Antarctic waters". Kungliga Svenska Vetenskapsakademiens Handlingar. Series 3. 19 (4): 1–92.
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