Milligania | |
---|---|
![]() | |
Milligania densiflora | |
Scientific 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]
Plants within this genus are perennial, rhizomatous, tufted herbs with short stems, often forming small clumps. [6] [7] [8] [9]
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]
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. [11]
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. [11] Milligania was considered to be divergent from other genera within the Asteliaceae family due to its semi-inferior ovary and dry fruit. [12]
Thickened, fleshy roots from a short thick rhizome. [7]
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. [14] This divide delineates significant differences in Tasmania's geology, climate, and vegetation. [14] Geological composition influences soil types, contributing to dramatic variations in vegetation across the state. [15] The western region typically experiences higher mean rainfall with acidic soils, leading to the prevalence of rainforest, moorland, and wet sclerophyll vegetation. [15] [16] Conversely, the eastern part of the state receives lower mean rainfall and has slightly more fertile soils, resulting in predominantly dry sclerophyll vegetation. [15] [16]
Plants within the Asteliaceae family exhibit a wide range of habitat preferences but generally thrive in environments with consistent moisture levels. [17] They are commonly found in tall, densely clustered habitats. [18] The five Milligania species occupy habitats ranging from lowland riparian valleys to alpine fellfields. [8]
The genus name 'Milligania' was initially documented in Hooker's J. Bot. Kew Gard. Misc. 5: 296 (1853). [19] However, its placement within the Asteliaceae family has faced challenges due to insufficient support in a cladistic analysis involving both morphological and molecular data. [12] It has been regarded as an outlier within the family, diverging from the typical characteristics observed in other genera. [20] 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. [21]
Asparagales |
| ||||||||||||||||||||||||||||||
Within the Asteliaceae family, studies conducted in 2012 and 2013 grouped Milligania with Astelia. [8] [22] A 2021 study placed Neoastelia and Milligania as sisters: [23]
Asteliaceae |
| ||||||||||||
Milligania johnstonii and Milligania longifolia are listed as rare under the Threatened Species Act 1995. [24] [25] Milligania densiflora is not considered to be at risk in the wild. [26] There is no known status for Milligania lindoniana or Milligania stylosa.