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The Apiales are an order of flowering plants. The families are those recognized in the APG III system.[1] This is typical of the newer classifications, though there is some slight variation and in particular, the Torriceliaceae may be divided.[2]

Apiales
Umbella.jpg
Inflorescence of a wild carrot, Daucus carota, in the Apiaceae family.
Scientific classification e
Kingdom: Plantae
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Clade: Campanulids
Order: Apiales
Nakai[1]
Families[1]

Under this definition, well-known members include carrots, celery, parsley, and Hedera helix (English ivy).

The order Apiales is placed within the asterid group of eudicots as circumscribed by the APG III system.[1] Within the asterids, Apiales belongs to an unranked group called the campanulids,[3] and within the campanulids, it belongs to a clade known in phylogenetic nomenclature as Apiidae.[4] In 2010, a subclade of Apiidae named Dipsapiidae was defined to consist of the three orders: Apiales, Paracryphiales, and Dipsacales.[5]

TaxonomyEdit

Under the Cronquist system, only the Apiaceae and Araliaceae were included here, and the restricted order was placed among the rosids rather than the asterids. The Pittosporaceae were placed within the Rosales, and many of the other forms within the family Cornaceae. Pennantia was in the family Icacinaceae. In the classification system of Dahlgren the Apiaceae and Araliaceae families were placed in the order Ariales, in the superorder Araliiflorae (also called Aralianae).

The present understanding of the Apiales is fairly recent and is based upon comparison of DNA sequences by phylogenetic methods.[6] The circumscriptions of some of the families have changed. In 2009, one of the subfamilies of Araliaceae was shown to be polyphyletic.[7]

GynoeciaEdit

The largest and obviously closely related families of Apiales are Araliaceae, Myodocarpaceae and Apiaceae, which resemble each other in the structure of their gynoecia. In this respect however, the Pittosporaceae is notably distinct from them.[8]

Typical syncarpous gynoecia exhibit four vertical zones, determined by the extent of fusion of the carpels. In most plants the synascidiate (i.e. "united bottle-shaped") and symplicate zones are fertile and bear the ovules.[9] Each of the first three families possess mainly bi- or multilocular ovaries in a gynoecium with a long synascidiate, but very short symplicate zone, where the ovules are inserted at their transition, the so-called cross-zone (or "Querzone").[8]

In gynoecia of the Pittosporaceae, the symplicate is much longer than the synascidiate zone, and the ovules are arranged along the first. Members of the latter family consequently have unilocular ovaries with a single cavity between adjacent carpels.[8]

ReferencesEdit

  1. ^ a b c d Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III" (PDF). Botanical Journal of the Linnean Society. 161 (2): 105–121. doi:10.1111/j.1095-8339.2009.00996.x. Retrieved 2013-07-06. 
  2. ^ Gregory M. Plunkett, Gregory T. Chandler, Porter P. Lowry, Steven M. Pinney, and Taylor S. Sprenkle (2004). "Recent advances in understanding Apiales and a revised classification". South African Journal of Botany 70(3):371-381.
  3. ^ Richard C. Winkworth, Johannes Lundberg, and Michael J. Donoghue (2008). "Toward a resolution of Campanulid phylogeny, with special reference to the placement of Dipsacales". Taxon 57(1):53-65.
  4. ^ Philip D. Cantino; James A. Doyle; Sean W. Graham; Walter S. Judd; Richard G. Olmstead; Douglas E. Soltis; Pamela S. Soltis; Michael J. Donoghue (2007), "Towards a phylogenetic nomenclature of Tracheophyta" (PDF), Taxon, 56 (3): 822–846, doi:10.2307/25065865 
  5. ^ Tank, D. C.; Donoghue, M. J. (2010). "Phylogeny and Phylogenetic Nomenclature of the Campanulidae based on an Expanded Sample of Genes and Taxa". Systematic Botany. 35 (2): 425. doi:10.1600/036364410791638306. 
  6. ^ Chandler, G. T.; Plunkett, G. M. (2004). "Evolution in Apiales: nuclear and chloroplast markers together in (almost) perfect harmony". Botanical Journal of the Linnean Society. 144 (2): 123. doi:10.1111/j.1095-8339.2003.00247.x. 
  7. ^ Nicolas, A. N.; Plunkett, G. M. (2009). "The demise of subfamily Hydrocotyloideae (Apiaceae) and the re-alignment of its genera across the entire order Apiales". Molecular Phylogenetics and Evolution. 53 (1): 134–151. doi:10.1016/j.ympev.2009.06.010. PMID 19549570. 
  8. ^ a b c Oskolski, Alexei A.; Sokoloff, Dmitry D.; Van Wyk, Ben-Erik (2010). "False paracarpy in Seemannaralia (Araliaceae): from bilocular ovary to unilocular fruit" (PDF). Annals of Botany. 106 (106): 29 –36. doi:10.1093/aob/mcq084. PMC 2889795 . Retrieved 28 April 2017. 
  9. ^ Pankhurst, R. J. (1992). Morphology of flowers and inflorescences (1st pbk. ed.). Cambridge, England: Cambridge University Press. pp. 153–155. ISBN 9780521438322.