View source for Asteliaceae

{{Short description|Family of flowering plants}}
{{Automatic taxobox
|image = Astelia_hemichrysa.JPG
|image_caption = ''[[Astelia hemichrysa]]''
|taxon = Asteliaceae
|authority = [[Barthélemy Charles Joseph Dumortier|Dumort.]]<ref name="APG3" />
|subdivision_ranks = Genera
|subdivision = See text
}}

'''Asteliaceae''' is a [[Family (biology)|family]] of [[flowering plant]]s, placed in the [[Order (biology)|order]] [[Asparagales]] of the [[monocot]]s.<ref name=APG3/>

The family has only recently been recognized by taxonomists. The [[APG III system]] of 2009 (unchanged from the [[APG system|1998]] and [[APG II system|2003]] versions) does recognize this family. The family includes three genera<ref name="POWO_77126733-1"/> with about 38 species,<ref>{{Cite journal|last1=Christenhusz|first1=Maarten J.M.|last2=Byng|first2=James W.|date=20 May 2016|title=The number of known plants species in the world and its annual increase|url=https://biotaxa.org/Phytotaxa/article/view/phytotaxa.261.3.1|journal=Phytotaxa|volume=261|issue=3|pages=201|doi=10.11646/phytotaxa.261.3.1|issn=1179-3163|doi-access=free}}</ref> occurring in the Southern Hemisphere. It is bird/insect pollinated and its conservation status as of 2017 is not threatened.<ref>{{Cite journal|last1=Reichgelt|first1=Tammo|last2=Lee|first2=William G.|date=6 August 2021|title=Geographic variation of leaf form among indigenous woody angiosperms in New Zealand|url=http://dx.doi.org/10.1080/0028825x.2021.1960384|journal=New Zealand Journal of Botany|volume=60 |issue=2 |pages=134–158|doi=10.1080/0028825x.2021.1960384|s2cid=238776046|issn=0028-825X}}</ref>{{irrelevant citation|date=September 2023|reason=Citation does not relate to conservation status of the family.}}

==Description==
A large variation in morphology is seen within this family.

=== Roots ===
The main cell type of the vascular tissue system present in roots are tracheids.<ref name=":52">{{Cite journal|last1=Carlquist|first1=Sherwin|last2=Schneider|first2=Edward L.|date=October 2010|title=Origins and Nature of Vessels in Monocotyledons. 12. Pit Membrane Microstructure Diversity in Tracheary Elements of ''Astelia''|url=http://dx.doi.org/10.2984/64.4.607|journal=Pacific Science|volume=64|issue=4|pages=607–618|doi=10.2984/64.4.607|hdl=10125/23130|s2cid=9521857|issn=0030-8870}}</ref> Roots are the only plant organs to have vessel elements and this is seen commonly in Monocots. The habitat of a monocot will determine different xylem characteristics.<ref name=":44">{{Cite journal|last=Carlquist|first=Sherwin|date=5 April 2012|title=Monocot Xylem Revisited: New Information, New Paradigms|url=http://dx.doi.org/10.1007/s12229-012-9096-1|journal=The Botanical Review|volume=78|issue=2|pages=87–153|doi=10.1007/s12229-012-9096-1|bibcode=2012BotRv..78...87C |s2cid=15562011|issn=0006-8101}}</ref><ref name=":52"/> The habitat of Asteliaceae gives rise to the variation seen in the xylem.<ref name=":44"/><ref name=":52"/> These tracheary elements have pores in their walls from fragments of the pit membrane.<ref name=":52"/> The vessels that are present within Asteliaceae have very primitive perforation plates.<ref name=":63">{{Cite journal|last1=Carlquist|first1=Sherwin|last2=Schneider|first2=Edward L.|date=March 2011|title=Origins and Nature of Vessels in Monocotyledons. 13. Scanning Electron Microscopy Studies of Xylem in Large Grasses|url=http://dx.doi.org/10.1086/658155|journal=International Journal of Plant Sciences|volume=172|issue=3|pages=345–351|doi=10.1086/658155|s2cid=55262434|issn=1058-5893}}</ref>

Rhizomes in ''Astelia'' create large intermingled structures that overtake the surrounding environment and vegetation.<ref name=":63"/>

=== Leaves ===
Leaves in Asteliaceae are long, slender, and alternately arranged.<ref name=":05">{{Cite journal|last1=Birch|first1=Joanne L.|last2=Keeley|first2=Sterling C.|last3=Morden|first3=Clifford W.|date=October 2012|title=Molecular phylogeny and dating of Asteliaceae (Asparagales): ''Astelia'' s.l. evolution provides insight into the Oligocene history of New Zealand|url=https://linkinghub.elsevier.com/retrieve/pii/S1055790312002096|journal=Molecular Phylogenetics and Evolution|language=en|volume=65|issue=1|pages=102–115|doi=10.1016/j.ympev.2012.05.031|pmid=22664642|bibcode=2012MolPE..65..102B }}</ref><ref name=":14">{{Cite journal|last1=Birch|first1=Joanne L.|last2=Keeley|first2=Sterling C.|date=19 July 2013|title=Dispersal pathways across the Pacific: the historical biogeography of ''Astelia'' s.l. (Asteliaceae, Asparagales)|url=http://dx.doi.org/10.1111/jbi.12169|journal=Journal of Biogeography|volume=40|issue=10|pages=1914–1927|doi=10.1111/jbi.12169|bibcode=2013JBiog..40.1914B |s2cid=85887986 |issn=0305-0270}}</ref>

A rare, unique trait in Asteliaceae is leaf hairs that are silver and white. They are usually present in this family and are distinct with branching so they are easy to notice.<ref name=":05"/>

No vessel elements are found in the leaves of this family. The only xylem cell type present is tracheids.<ref name=":44"/><ref name=":63"/>

=== Stems ===
In comparison to roots, the tracheids present in the stems are less porous and therefore have less pit membranes.<ref name=":52"/> Additionally, stems in Asteliaceae do not have vessel elements.<ref name=":44"/><ref name=":63"/>

=== Flowers and reproduction ===
Flowers in Asteliaceae are typically dioecious but it varies depending on the genus.<ref name=":05"/> ''Milligania'' and ''Neoastelia'' have perfect bisexual flowers while ''Astelia'' (including ''Collospermum'') usually have imperfect unisexual flowers.<ref name=":05"/> One ''Astelia'' species in specific produces both female flowers and imperfect flowers together in the same population.<ref name=":05"/>

Inflorescence in this family is always terminal and has a branched cluster of flowers but the variation in this category is wide, particularly with unisexual inflorescences.<ref name=":14"/> There is a large, leaf-like sheathing bract that surrounds and encloses the flower cluster.<ref name=":14"/> Typically, the distinct hairs on the leaves can also be seen on the inflorescence and flowers.<ref name=":05"/>

Asteliaceae has either a sterile pistil or a pistil with a superior ovary, one short or inconspicuous style, and a three lobed stigma.<ref name=":14"/><ref name=":23">{{Cite journal|last=Birch|first=Joanne L.|date=15 July 2015|title=A revision of infrageneric classification in ''Astelia'' Banks & Sol. ex R.Br. (Asteliaceae)|url=http://phytokeys.pensoft.net/articles.php?id=4768|journal=PhytoKeys|issue=52|pages=105–132|doi=10.3897/phytokeys.52.4768|issn=1314-2003|pmc=4549886|pmid=26312037 |doi-access=free }}</ref> Stamens in Asteliaceae either have dorsifixed or basifixed anthers.<ref name=":14"/><ref name=":23"/>

The number of locules in the ovary varies in each genus. ''Astelia'' usually has three locules, but it also can have a single locule. Even within the genus ''Neoastelia'', there can be between three and seven locules.<ref name=":23"/>

=== Fruits and seeds ===
Usually, fruits in Asteliaceae are fleshy, as seen within the genera ''Astelia'' and ''Neoastelia''. However, the fruits can also be dry capsules as seen in the genus ''Milligania''.<ref name=":05"/>

Seed storage behaviour in Asteliaceae is quite odd as the seed is sensitive to freezing but this behaviour is not always seen. The smallest effect of this behaviour can be seen in the plants found growing in Hawaii.<ref>{{Cite journal|last1=Chau|first1=Marian M.|last2=Chambers|first2=Timothy|last3=Weisenberger|first3=Lauren|last4=Keir|first4=Matthew|last5=Kroessig|first5=Timothy I.|last6=Wolkis|first6=Dustin|last7=Kam|first7=Roy|last8=Yoshinaga|first8=Alvin Y.|date=September 2019|title=Seed freeze sensitivity and ex situ longevity of 295 species in the native Hawaiian flora|journal=American Journal of Botany|language=en|volume=106|issue=9|pages=1248–1270|doi=10.1002/ajb2.1351|issn=0002-9122|pmc=6856683|pmid=31502257}}</ref>

==Taxonomy==
The family Asteliaceae was created by [[Barthélemy Charles Joseph Dumortier|Dumortier]] in 1829.<ref name="IPNI_77126733-1">{{cite web |title=''Asteliaceae'' Dumort&period; |work=[[International Plant Names Index|The International Plant Names Index]] |url=https://www.ipni.org/n/77126733-1 |access-date=2021-12-04 }}</ref> In the [[APG IV system]], the family is placed in the order [[Asparagales]], part of the [[monocotyledon|monocot]] clade.<ref name=APGIV>{{Cite journal |last=Angiosperm Phylogeny Group  |year=2016 |title=An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG IV |journal=[[Botanical Journal of the Linnean Society]] |volume=181 |issue=1 |pages=1–20 |doi=10.1111/boj.12385 |doi-access=free }}</ref> Within the Asparagales, it is placed in a basal group of families, which diverge after [[Orchidaceae]], and is either sister to [[Hypoxidaceae]]<ref>{{Cite web |last1=Stevens |first1=Peter F. |title=Asparagales |website=Angiosperm Phylogeny Website |url=http://www.mobot.org/MOBOT/research/APweb/orders/asparagalesweb.htm#Asparagales |access-date=2021-12-04 }}</ref> or, in a 2021 study, to the clade [[Lanariaceae]] plus Hypoxidaceae:<ref name=BircKocy21>{{Citation |last1=Birch |first1=J.L. |last2=Kocyan |first2=A. |date=2021 |title=Biogeography of the monocotyledon astelioid clade (Asparagales): A history of long-distance dispersal and diversification with emerging habitats |journal=Molecular Phylogenetics and Evolution |volume=163 |page=107203 |doi=10.1016/j.ympev.2021.107203 |pmid=33992785 |s2cid=234746942 |name-list-style=amp |doi-access=free |bibcode=2021MolPE.16307203B }}</ref>
{{clade
|label1=Asparagales
|1={{clade
   |1=Orchidaceae
   |2={{clade
      |1={{clade
         |1=[[Boryaceae]]
         |2={{clade
            |1=[[Blandfordiaceae]]
            |2={{clade
               |1=Asteliaceae
               |2={{clade
                  |1=[[Lanariaceae]]
                  |2=[[Hypoxidaceae]]
                  }}
               }}
            }}
         }}
      |2=remaining Asparagales families
      }}
   }}
}}

Within the family, studies in 2012 and 2013 grouped ''Milligania'' with ''Astelia''.<ref name=":05"/><ref name=":14"/> The 2021 study placed ''Neoastelia'' and ''Milligania'' as sisters:<ref name=BircKocy21/>
{{clade
|label1=Asteliaceae
|1={{clade
   |1={{clade
      |1=''Neoastelia''
      |2=''Milligania''
      }}
   |2=''Astelia''
   }}
}}

===Genera===
{{As of|2021|December}}, [[Plants of the World Online]] accepts three genera:<ref name="POWO_77126733-1">{{cite web |title=''Asteliaceae'' Dumort&period; |work=Plants of the World Online |publisher=Royal Botanic Gardens, Kew|url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77126733-1 |access-date=2021-12-04 }}</ref>

* ''[[Astelia]]'' <small>Banks & Sol. ex R.Br.</small>
* ''[[Milligania]]'' <small>Hook.f.</small>
* ''[[Neoastelia]]'' <small>J.B.Williams</small>

The genus ''Collospermum'' has been synonymized with ''Astelia''.<ref name="POWO_24151-1">{{cite web |title=''Collospermum'' Dumort&period; |work=Plants of the World Online |publisher=Royal Botanic Gardens, Kew|url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:24151-1 |access-date=2021-12-04 }}</ref>

==Origin and diversity==
Due to its prevalence on the eastern [[Gondwana]]n landmasses, Australia, New Zealand, and South America, the Asteliaceae family has been classified as a "Austral" floristic element.<ref name=":05"/> This idea is supported by the split of ''Milligania'' from other astelioid taxa, which is estimated to be 79 million years old, based on age estimations of 102 and 92 million years old for the stem and crown lineages.<ref name=":05"/> Long-distance overwater dispersal was likely involved in the spread of Asteliaceae across the Pacific, although little is known about the paths of such dispersal events.<ref name=":05"/> ''Astelia'', which originated in New Zealand around 27.1 million years ago, is the largest and oldest genus in the family Asteliaceae. This is of note as the family Asteliaceae originated from Australia which is in proximity to New Zealand.<ref name=":14"/>

==Distribution==
Asteliaceae has a very wide distribution of species that live near large bodies of water.<ref name=":23"/> They are found on continents in the southern hemisphere,<ref name=":05"/><ref name=":14"/> while they are found in islands as well in the Pacific Ocean, Indian Ocean, Australia, and New Zealand.<ref name=":23"/> 30 of the 38 species in Asteliaceae are found in Australia, New Zealand, and Argentina which all border the South Pacific Ocean.<ref name=":14" /> The other 8 species are found to be living on archipelagos scattered around the Pacific Ocean and Indian Ocean, specifically in Fiji, Hawaii, and New Caledonia.<ref name=":14" /><ref name=":23"/> Asteliaceae managed to disperse to both the Western and Eastern Pacific Islands as a result of direct and stepping-stone dispersion paths from New Zealand through Fiji and Hawaii, respectively.<ref name=":14" />

Taxa within Asteliaceae are found in both the Austral and Pacific areas.<ref name=":14" /> However, New Zealand has been found to be the centre of genetic diversity, as three of the four genera of Asteliaceae have been found there.<ref name=":14" /> Interestingly, species diversity has also been found to be highest in New Zealand.<ref name=":14" /> Species within the genus ''Astelia'' have been discovered in Australia, New Zealand, South America, the Mascarene Islands in the Indian Ocean, and 7 archipelagos in the Pacific, showing that it is the biggest and most extensively dispersed of the four genera of Asteliaceae.<ref name=":05" />

Species within the genus ''Astelia'' are able to live in many different habitats such as coastal and lowland woods, low level swamps, alpine fellfields, and high elevation bogs.<ref name=":05" /> Four ''Astelia'' species formerly placed in ''Collospermum'' grow as epiphytes in lowland forests in New Zealand and in lowland and tropical montane cloud forests in Fiji, Vanuatu, and Samoa.<ref name=":05" /> ''Milligania'' consists of 5 species that grow only in Tasmania. They grow in a variety of environments including lowland riparian valleys and alpine fellfields. ''Neoastelia'' is a genus made of just a single species of terrestrial herbs found only in temperate rainforests in northeastern New South Wales.<ref name=":05" />

Although taxa within Asteliaceae are found across various Gondwanan landmasses, which include Australia, New Zealand, and South America, and the possible Cretaceous beginnings for the family, the Tertiary saw the emergence of new genera.<ref name=":05" /> Dispersion across long distances is the most likely hypothesis for the modern distribution for Asteliaceae.<ref name=":05" />

A solitary fossilized pollen grain, perhaps belonging to the Asteliaceae family, has been discovered in Oligocene to Pliocene sediments on West Point Island in the Falkland Islands. This fossil pollen datum, which is classified as either "''Astelia''-type" or "''Monosulcites'' sp. A.", might suggest the presence of ''Astelia'' in South America during the Tertiary period.<ref name=":05" />

==Habitat==
Different species of Asteliaceae favour different habitats. The range that Asteliaceae covers is extensive but typically an area with a constant supply of moisture will increase growth.<ref name=":44"/> Some prefer low habitats where cushion plants commonly grow, which encompasses areas like the subalpine, alpines, and bogs.<ref name=":23"/> One thing in common with all the species in this family is that they typically occupy tall and clustered habitats.<ref name=":23" />

Unlike most plants, some species are epiphytic and this could be the main way the plant grows. Many species from the genus ''Astelia'' favour terrestrial and rock as a substrate to grow upon. If the epiphytic plant is detached from its source, it will find other ways to get moisture and nutrients.<ref name=":23" /> For example, if the plant fell on the ground, it would not be affected and would continue growing for a long duration of time.<ref name=":23" />

==References==
{{Reflist|refs=
<ref name=APG3>{{Cite journal |last=Angiosperm Phylogeny Group III|year=2009 |title=An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III |journal=Botanical Journal of the Linnean Society|volume=161 |issue=2 |pages=105–121|doi=10.1111/j.1095-8339.2009.00996.x |doi-access=free |hdl=10654/18083 |hdl-access=free }}</ref>
}}

==External links==
*{{Commons category-inline|Asteliaceae}}
*[https://web.archive.org/web/20070103200438/http://delta-intkey.com//angio/www/asteliac.htm Asteliaceae] in L. Watson and M.J. Dallwitz (1992 onwards). ''[https://web.archive.org/web/20070103200438/http://delta-intkey.com/angio/ The families of flowering plants]: descriptions, illustrations, identification, information retrieval.'' Version: 9 March 2006. https://web.archive.org/web/20070103200438/http://delta-intkey.com/

{{Angiosperm families}}
{{Taxonbar|from=Q131348}}

[[Category:Asteliaceae| ]]
[[Category:Asparagales families]]