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Milligania

Milligania
Milligania densiflora
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Asteliaceae
Genus: Milligania
Hook. f.
Species

See text.

Milligania is a genus of native perennial plants containing five species which are all found in Tasmania:[1][2][3][4][5]

Formerly belonging to the Liliaceae family, Milligania is now a part of the Asteliaceae family.[4] Three of these species are alpine and subalpine, with the remaining two rare species growing along rivers in the south-west of the state.[4] All five species are restricted to very wet habitats and are typically found growing on waterlogged peat.[4] They are known to form extensive rough mats.[4]

Description

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Plants within this genus are perennial, rhizomatous, tufted herbs with short stems, often forming small clumps.[6][7][8][9]

Leaves

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The broad, leathery leaves exhibit a triangular shape with pleats resembling those found in the Astelia genus.[4][6] Leaves are alternately arranged[8] and sizes vary from quite small, measuring less than 5 cm in length, to large specimens reaching up to 1.25 m in length.[4] These leaves are sheathing in structure, with some silky hairs.[7]

Flowers and reproduction

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The star-like flowers boast six tepals and are prominently displayed in inflorescences above the leaves.[4][6] The flowers are pedicellate with basally fused tepals[9] which are primarily white, occasionally tinged with red at the tube mouth, with dense silky hairs that are rare in Aparagales.[7][8] These inflorescences can reach heights of up to 50 cm, with flowers densely arranged in a panicle formation.[7] Each flower, measuring up to 1.5 cm wide, is abundant and spreading during the summer season.[7] Milligania species are all hermaphroditic and produce bisexual flowers.[10]

Fruit and seeds

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Milligania has a dry capsule fruit containing several seeds[9] which contrasts to the fleshy fruit commonly found in the genera Astelia and Neoastelia in the Asteliaceae family.[4][5][8] Milligania, and some Astelia species possess trilocular ovaries.[8] Skottsberg proposed that features such as the capsular fruit, bisexual flowers and simple hairs observed in Milligania are primitive traits, or plesiomorphic.[10] Milligania was considered to be divergent from other genera within the Asteliaceae family due to its semi-inferior ovary and dry fruit.[11]

Roots

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Thickened, fleshy roots from a short thick rhizome.[7]

Distribution and habitat

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Distribution map of Milligania species in Tasmania.[12]

While Asteliaceae taxa are distributed across Austral and Pacific regions, the primary centre of generic diversity is situated in Australia.[8] All five Milligania species are endemic to Tasmania.[8] According to a distribution map provided by the Atlas of Living Australia, Milligania is mainly distributed on the western side of the state, west of the geographical feature known as Tyler's Corridor.[13] This divide delineates significant differences in Tasmania's geology, climate, and vegetation.[13] Geological composition influences soil types, contributing to dramatic variations in vegetation across the state.[14] The western region typically experiences higher mean rainfall with acidic soils, leading to the prevalence of rainforest, moorland, and wet sclerophyll vegetation.[14][15] Conversely, the eastern part of the state receives lower mean rainfall and has slightly more fertile soils, resulting in predominantly dry sclerophyll vegetation.[14][15]

Plants within the Asteliaceae family exhibit a wide range of habitat preferences but generally thrive in environments with consistent moisture levels.[16] They are commonly found in tall, densely clustered habitats.[17] The five Milligania species occupy habitats ranging from lowland riparian valleys to alpine fellfields.[8]

Surface geology of Tasmania

Taxonomy

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The genus name 'Milligania' was initially documented in Hooker's J. Bot. Kew Gard. Misc. 5: 296 (1853).[18] However, its placement within the Asteliaceae family has faced challenges due to insufficient support in a cladistic analysis involving both morphological and molecular data.[11] It has been regarded as an outlier within the family, diverging from the typical characteristics observed in other genera.[9] A cladistic study conducted by Maciunas et al. in 2011 revealed a potential sister relationship between the Neoastelia/Milligania and Collospermum/Astelia clades, based on analysis of morphological data.[19]

Asparagales

Orchidaceae

remaining Asparagales families

Within the Asteliaceae family, studies conducted in 2012 and 2013 grouped Milligania with Astelia.[8][20] A 2021 study placed Neoastelia and Milligania as sisters:[21]

Asteliaceae

Neoastelia

Milligania

Astelia

Conservation status and threats

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Milligania johnstonii and Milligania longifolia are listed as rare under the Threatened Species Act 1995.[22][23] Milligania densiflora is not considered to be at risk in the wild.[24] There is no known status for Milligania lindoniana or Milligania stylosa.

References

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Wikispecies has information related to Milligania .
  1. ^ Hooker, William Jackson (1853). Hooker's journal of botany and Kew Garden Miscellany. Vol. 5. London: Reeve, Benham, and Reeve.
  2. ^ "World Checklist of Selected Plant Families: Royal Botanic Gardens, Kew". wcsp.science.kew.org. Retrieved 2021-05-09.
  3. ^ "Search results — The Plant List". www.theplantlist.org. Retrieved 2021-05-09.
  4. ^ a b c d e f g h i "Key to Tasmanian Dicots". www.utas.edu.au. Retrieved 2024-03-29.
  5. ^ a b "Milligania - Encyclopedia of Life". eol.org. Retrieved 2024-03-29.
  6. ^ a b c "Home". Alpine Garden Society. Retrieved 2024-03-30.
  7. ^ a b c d e f "HortFlora". hortflora.rbg.vic.gov.au. Retrieved 2024-03-29.
  8. ^ a b c d e f g h i Birch, Joanne L.; Keeley, Sterling C.; Morden, Clifford W. (2012-10-01). "Molecular phylogeny and dating of Asteliaceae (Asparagales): Astelia s.l. evolution provides insight into the Oligocene history of New Zealand". Molecular Phylogenetics and Evolution. 65 (1): 102–115. Bibcode:2012MolPE..65..102B. doi:10.1016/j.ympev.2012.05.031. ISSN 1055-7903. PMID 22664642.
  9. ^ a b c d Bayer, C.; Appel, O.; Rudall, P. J. (1998), Kubitzki, Klaus (ed.), "Asteliaceae", Flowering Plants · Monocotyledons: Lilianae (except Orchidaceae), Berlin, Heidelberg: Springer, pp. 141–145, doi:10.1007/978-3-662-03533-7_17, ISBN 978-3-662-03533-7, retrieved 2024-04-03
  10. ^ a b Skottsberg, Carl Johan Fredrik. "Studies in the genus Astelia Banks et Solander". (No Title).
  11. ^ a b Rudall, PAULA J.; Chase, MARK W.; Cutler, DAVID F.; Rusby, JANET; De bruijn, ANETTE Y. (1998-05-01). "Anatomical and molecular systematics of Asteliaceae and Hypoxidaceae". Botanical Journal of the Linnean Society. 127 (1): 1–42. doi:10.1006/bojl.1997.0164. ISSN 0024-4074.
  12. ^ "Search: genus: Milligania | Occurrence records | Atlas of Living Australia". biocache.ala.org.au. Retrieved 2024-04-03.
  13. ^ a b Tyler, Peter A. (1992). "A lakeland from the dreamtime the second founders' lecture". British Phycological Journal. 27 (4): 353–368. doi:10.1080/00071619200650301. ISSN 0007-1617.
  14. ^ a b c Rees, Andrew B. H.; Cwynar, Les C. (2010). "A test of Tyler's Line – response of chironomids to a pH gradient in Tasmania and their potential as a proxy to infer past changes in pH". Freshwater Biology. 55 (12): 2521–2540. Bibcode:2010FrBio..55.2521R. doi:10.1111/j.1365-2427.2010.02482.x. ISSN 0046-5070.
  15. ^ a b Larsen, Kai (1999). "Reid, J. B., Hill, R. S., Brown, M. J. & Hovenden, M. J. (eds). 1999. Vegetation of Tasmania". Nordic Journal of Botany. 19 (5): 622. doi:10.1111/j.1756-1051.1999.tb01151.x. ISSN 0107-055X.
  16. ^ Carlquist, Sherwin (2012-06-01). "Monocot Xylem Revisited: New Information, New Paradigms". The Botanical Review. 78 (2): 87–153. Bibcode:2012BotRv..78...87C. doi:10.1007/s12229-012-9096-1. ISSN 1874-9372.
  17. ^ Birch, Joanne L.; Keeley, Sterling C.; Morden, Clifford W. (2012-10-01). "Molecular phylogeny and dating of Asteliaceae (Asparagales): Astelia s.l. evolution provides insight into the Oligocene history of New Zealand". Molecular Phylogenetics and Evolution. 65 (1): 102–115. Bibcode:2012MolPE..65..102B. doi:10.1016/j.ympev.2012.05.031. ISSN 1055-7903. PMID 22664642.
  18. ^ "WFO Plant List | World Flora Online". wfoplantlist.org. Retrieved 2024-03-30.
  19. ^ Maciunas, Elizabeth; Conran, John G.; Bannister, Jennifer M.; Paull, Rosemary; Lee, Daphne E. (2011-04-29). "Miocene Astelia (Asparagales: Asteliaceae) macrofossils from southern New Zealand". Australian Systematic Botany. 24 (1): 19–31. doi:10.1071/SB10035. ISSN 1446-5701.
  20. ^ Birch, Joanne L.; Keeley, Sterling C. (2013). Richardson, James (ed.). "Dispersal pathways across the Pacific: the historical biogeography of Astelia s.l. (Asteliaceae, Asparagales)". Journal of Biogeography. 40 (10): 1914–1927. Bibcode:2013JBiog..40.1914B. doi:10.1111/jbi.12169. ISSN 0305-0270.
  21. ^ Birch, Joanne L.; Kocyan, Alexander (2021-10-01). "Biogeography of the monocotyledon astelioid clade (Asparagales): A history of long-distance dispersal and diversification with emerging habitats". Molecular Phylogenetics and Evolution. 163: 107203. Bibcode:2021MolPE.16307203B. doi:10.1016/j.ympev.2021.107203. ISSN 1055-7903. PMID 33992785.
  22. ^ "Milligania johnstonii - Threatened Species Link". www.threatenedspecieslink.tas.gov.au. Retrieved 2024-04-03.
  23. ^ "Milligania longifolia - Threatened Species Link". www.threatenedspecieslink.tas.gov.au. Retrieved 2024-04-03.
  24. ^ "Milligania densiflora". Australian Native Plants Society (Australia). Retrieved 2024-04-03.