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 also be divided.[2]
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]
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 families Apiaceae and Araliaceae 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]
The largest and obviously closely related families of Apiales are Araliaceae, Myodocarpaceae andApiaceae, which resemble each other in the structure of their gynoecia. In this respect however, the Pittosporaceae is notably distinct from them.[8]