Families of Asparagales

The

• Family Amaryllidaceae J.St.-Hil. (including Agapanthaceae F.Voigt, Alliaceae Borkh.)^{[notes 1]}
• Family Asparagaceae Juss. (including Agavaceae Dumort. [which includes Anemarrhenaceae, Anthericaceae, Behniaceae and Herreriaceae], Aphyllanthaceae Burnett, Hesperocallidaceae Traub, Hyacinthaceae Batsch ex Borkh., Laxmanniaceae Bubani, Ruscaceae M.Roem. [which includes Convallariaceae] and Themidaceae Salisb.)
• Family Asphodelaceae Juss. (including Hemerocallidaceae R.Br. and Xanthorrhoeaceae Dumort)^{[notes 2]}
• Family Asteliaceae Dumort.
• Family
  Blandfordiaceae
  R. Dahlgren & Clifford
• Family Boryaceae M.W. Chase, Rudall & Conran
• Family
  Doryanthaceae
  R. Dahlgren & Clifford
• Family Hypoxidaceae R.Br.
• Family Iridaceae Juss.
• Family
  Ixioliriaceae
  Nakai
• Family
  Lanariaceae
  R. Dahlgren & A.E.van Wyk
• Family
  Orchidaceae
  Juss.
• Family Tecophilaeaceae Leyb.
• Family
  Xeronemataceae
  M.W. Chase, Rudall & M.F.Fay

The earlier 2003 version, APG II, allowed 'bracketed' families, i.e. families which could either be segregated from more comprehensive families or could be included in them. These are the families given under "including" in the list above. APG III does not allow bracketed families, requiring the use of the more comprehensive family; otherwise the circumscription of the Asparagales is unchanged. A separate paper accompanying the publication of the 2009 APG III system provided subfamilies to accommodate the families which were discontinued.^[5] The first APG system of 1998 contained some extra families, included in square brackets in the list above.

Comparison with older systems

Two older systems which use the order Asparagales are the Dahlgren system^[6] and the Kubitzki system.^[7] The families included in the circumscriptions of the order in these are wrong info

Descriptions of families and subfamilies

Orchidaceae

The orchid family is one of the two largest families of

The genus

The Asteliaceae is a family of two to four genera of plants found in the Southern Hemisphere. They are more or less rhizomatous, with spiral leaves and an inflorescence that may form a raceme or a spike. There are large bracts at the base of the inflorescence. The individual flowers are small, with tepals joined at the base.

Hypoxidaceae

The family includes some 150 species with a worldwide distribution, excluding Europe and northern Asia. Species can be recognized by their

Ixioliriaceae

The family includes a single genus,

.

Tecophilaeaceae

Main article: Tecophilaeaceae

The nine genera are found in

anthers open by pores. The genus Cyanastrum

is sometimes placed in its own family Cyanastraceae.

Doryanthaceae

Main article:

Doryanthaceae

The two species of Doryanthes, the only genus of the family, are huge rosette-forming herbs that are a conspicuous element of the flora in the vicinity of Sydney, being hard not to notice when in flower. The leaves have entire margins but disintegrate into fibres at the apex. The sub-

ovaries

.

Iridaceae

Main article: Iridaceae

The iris family contains about 70

The family consists of a single genus

are strongly exserted (i.e. extend out of the flower). The family is still poorly known.

Asphodelaceae sensu lato

Main article: Asphodelaceae

The Asphodelaceae, or asphodel family, has been recognized in some form by many

phylogenetic research, the 2009 revision of the APG classification grouped together the former families Hemerocallidaceae, Xanthorrhoeaceae sensu stricto and Asphodelaceae sensu stricto as the Xanthorrhoeaceae.^[1] A paper published at the same time proposed that the original three families should be retained as subfamilies within Xanthorrhoeaceae sensu lato.^[5] Xanthorrhoeaceae has priority as a family name, but has been considered not to reflect the nature of the family, and in 2014 it was agreed to propose the formal conservation of Asphodelaceae over Xanthorrhoeaceae to the 2017 International Botanical Congress, which is responsible for plant nomenclature. In anticipation of this decision, the APG IV system uses the name Asphodelaceae.^[11]

Hemerocallidoideae

Main article: Hemerocallidoideae

The Hemerocallidoideae, or day lily, subfamily of the Xanthorrhoeaceae sensu lato is treated in some systems as a separate family, the Hemerocallidaceae. It includes perennial herbaceous plants which are glabrous and have short

The Xanthorrhoeoideae, or grasstree, subfamily of the Xanthorrhoeaceae sensu lato is treated in some systems as a separate family, the Xanthorrhoeaceae sensu stricto. It contains only one genus, Xanthorrhoea, endemic to Australia. Many species have an erect woody stem which is covered with persistent dried leaves unless there have been fires, topped by a crown of long thin leaves. The spike-like inflorescence is erect and densely crowded with small flowers. The fruit is a capsule. Plants are adapted to bush fires, which can stimulate flowering.

Asphodeloideae

The Asphodeloideae, or asphodel, subfamily of the Xanthorrhoeaceae sensu lato is treated in some systems as a separate family, the Asphodelaceae. Members of the family are natives of temperate to tropical regions of the

The amaryllis family has been recognized in many taxonomic systems, but the limits of the family have varied. In the narrowest definition, the Amaryllidaceae sensu stricto is characterized by an umbellate inflorescence with an inferior ovary. Two other groups have similar inflorescences but a superior ovary, and have at times been put into separate families: the Agapanthaceae and the Alliaceae. Based on

The agapanthus subfamily of the Amaryllidaceae sensu lato is treated in some systems as a separate family, the Agapanthaceae. Agapanthus, native to South Africa, is the sole genus of the subfamily. They are relatively robust herbaceous perennials with short rhizomes and leaves forming a rosette, individually linear-oblong, flat, rather fleshy. The flowers are quite large, blue or white, forming an umbel at the end of a stem (scape) which is longer than the leaves. The inflorescences are protected by bracts joined along one side. The ovary is superior. Plants do not have the characteristic garlic odor of the allium subfamily (Allioideae). They are set apart from the amaryllis subfamily (Amaryllidoideae) by their superior ovary, the presence of saponins and the absence of the alkaloids typical of amaryllids. Agapanthus is widely grown as an ornamental in temperate gardens.

Allioideae

The allium subfamily of the Amaryllidaceae sensu lato is treated in some systems as a separate family, the Alliaceae. Members of the subfamily are found worldwide, in temperate, subtropical and tropical regions. They are herbaceous perennials, usually with

The amaryllis subfamily of the Amaryllidaceae sensu lato is treated in some systems as a separate family, the Amaryllidaceae sensu stricto. The subfamily includes 59 genera and approximately 800 species from temperate and tropical regions worldwide. They are herbaceous perennials with

Asparagaceae sensu lato

The members of this group have a complex taxonomic history, having been assigned to widely differing families in different classification systems. Proposed subgroups are difficult to recognise, having similar 'lily-like' flowers, with the result that some members of the group have been included in different subgroups at different times.

The subfamily Aphyllanthoideae of the Asparagaceae sensu lato is treated in some systems as a separate family, the Aphyllanthaceae. It comprises a single species, Aphyllanthes monspeliensis, found in arid areas of the western Mediterranean. The inflorescence is made up of small clusters of blue flowers at the end of a long stem (scape). An unusual feature of the species is that the stem (scape) is actually the main photosynthetic organ, since the paper-like leaves at the base lack chlorophyll.

Brodiaeoideae

The subfamily Brodiaeoideae of the Asparagaceae sensu lato is treated in some systems as a separate family, under the name Themidaceae. It comprises about a dozen genera which are native to western North America. Plants are superficially similar to those of the allium subfamily, being perennial herbs with an umbellate

The scilla subfamily, Scilloideae, of the Asparagaceae sensu lato is treated in some systems as a separate family, under the name Hyacinthaceae. The group includes from 770 to 1,000 species, distributed predominantly in Mediterranean climates, especially South Africa, the

The agave subfamily, Agavoideae, of the Asparagaceae sensu lato is treated in some systems as a separate family, under a variety of names, including Agavaceae. It includes species formerly placed in several other families (e.g. Anthericaceae and Hesperocallidaceae). Many species currently assigned to this group have been placed in other groups at different times. Stevens notes "The broad concept of Agavoideae adopted here may not seem very satisfactory, but I fear that none of the alternative solutions is much better ...".

The subfamily Lomandroideae of the Asparagaceae sensu lato is treated in some systems as a separate family, Laxmanniaceae. The group consists of some 15 genera and about 180 species from Australasia, south east Asia, and South America. The best known genus is Cordyline. The tepals of the flower persist in the fruit. Species of Cordyline are grown as house plants and as garden plants in temperate to tropical regions.

Asparagoideae

The asparagus subfamily of the Asparagaceae sensu lato is treated in some systems as a separate family, the Asparagaceae sensu stricto. The subfamily contains only two genera, one,

is used as a vegetable, the young shoots being cut before they become woody. Other species are used as house plants and as greenery in the cut flower trade.

Nolinoideae

Main article: Nolinoideae

The subfamily Nolinoideae of the Asparagaceae sensu lato is treated in some systems as a separate family, under a variety of names, including Ruscaceae sensu lato. As with the subfamily Agavoideae, the Nolinoideae contains genera previously classified in a number of different families (including Ruscaceae sensu stricto, Nolinaceae sensu stricto, Convallariaceae sensu stricto and Eriospermaceae sensu stricto). When broadly defined, the group contains some 26 genera and almost 500 species, distributed mainly in the temperate to tropical regions of the Northern Hemisphere. There are few morphological features separating the subfamily from other groups within the Asparagaceae sensu lato. The small flowers are radially symmetrical, with six tepals, usually joined at the base, six stamens and a superior ovary. The fruit is usually a berry with few seeds. Species vary from herbaceous perennials to tree-like forms (e.g. Dracaena). There are several examples of convergent evolution between species in this subfamily and those in other subfamilies of the Asparagaceae sensu lato. Ruscus (butcher's broom) has photosynthetic branches (phylloclades), similar to those of Asparagus (Asparagoideae); Dracaena draco has a tree-like habit resembling Yucca (Agavoideae) and Cordyline (Lomandroideae). Some genera are used in horticulture: Sansevieria and Aspidistra are used as house plants in temperate areas and as garden plants in warmer regions; Polygonatum and Ophiopogon are used as garden plants in temperate areas.

See also

• Taxonomy of Liliaceae

Notes

1. ^ The name 'Alliaceae' has also been used for the expanded family comprising the Alliaceae sensu stricto, Amaryllidaceae and Agapanthaceae (e.g. in the APG II system). 'Amaryllidaceae' is used as a conserved name in APG III.
2. ^ The name Xanthorrhoeaceae has priority as of June 2016^[update], but Asphodelaceae has been proposed for conservation and is used in anticipation in the APG IV system of classification.

References

1. ^ ^{a b c d} Angiosperm Phylogeny Group III 2009
2. ^ WCSP 2010
3. ^ Dahlgren, Clifford & Yeo 1985, Order Asparagales.
4. ^ ^{a b c} Stevens 2015.
5. ^ ^{a b c d} Chase, Reveal & Fay 2009
6. ^ Dahlgren, Clifford & Yeo 1985
7. ^ Kubitzki 1998
8. ^ ^{a b} Goldblatt 2002
9. ^ Dimitri 1987
10. ^ Hessayon 1999
11. doi:10.1111/boj.12385
    .
12. ^ Angiosperm Phylogeny Group II 2003
13. ^ Tapiero, Townsend & Tew 2004

Bibliography

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