The order is very diverse, with well-known members including willows, violets, aspens and poplars, poinsettia, corpse flower, coca plant, cassava, flaxseed, castor bean, Saint John's wort, passionfruit, mangosteen, and manchineel tree.

The order is not part of any of the classification systems based only on plant morphology and the relationships of its diverse members can be hard to recognize except with molecular phylogenetic evidence.

They included analyses of 82 plastid genes from 58 species (ignoring the problematic Rafflesiaceae), using partitions identified a posteriori by applying a Bayesian mixture model.

[7][8] Oxalidales (outgroup) Euphorbiaceae Peraceae Picrodendraceae Phyllanthaceae Linaceae Ixonanthaceae Salicaceae Scyphostegiaceae Samydaceae Lacistemataceae Passifloraceae Turneraceae Malesherbiaceae Violaceae Goupiaceae Achariaceae Humiriaceae Hypericaceae Podostemaceae Calophyllaceae Clusiaceae Bonnetiaceae Ochnaceae Quiinaceae Medusagynaceae Rhizophoraceae Erythroxylaceae Ctenolophonaceae Pandaceae Irvingiaceae Chrysobalanaceae Euphroniaceae Dichapetalaceae Trigoniaceae Balanopaceae Malpighiaceae Elatinaceae Centroplacaceae Caryocaraceae Putranjivaceae Lophopyxidaceae The older phylogenetic tree shown below is from Wurdack and Davis (2009).

Putranjivaceae Lophopyxidaceae Irvingiaceae Centroplacaceae Caryocaraceae Pandaceae Ixonanthaceae Humiriaceae Linaceae Elatinaceae Malpighiaceae Ctenolophonaceae Erythroxylaceae Rhizophoraceae Balanopaceae Trigoniaceae Dichapetalaceae Euphroniaceae Chrysobalanaceae Ochnaceae Medusagynaceae Quiinaceae Bonnetiaceae Clusiaceae Calophyllaceae Hypericaceae Podostemaceae Picrodendraceae Phyllanthaceae Peraceae Rafflesiaceae Euphorbiaceae Achariaceae Goupiaceae Violaceae Malesherbiaceae Turneraceae Passifloraceae Lacistemataceae Samydaceae Scyphostegiaceae Salicaceae Malpighiales is monophyletic and in molecular phylogenetic studies, it receives strong statistical support.

[9] Some family delimitations within the order have changed, as well, most notably, the segregation of Calophyllaceae from Clusiaceae sensu lato when it was shown that the latter is paraphyletic.

[3] Members often have dentate leaves, with the teeth having a single vein running into a congested and often deciduous apex (i.e., violoid, salicoid, or theoid).

[17] Some recent studies have placed Malpighiales as sister to Oxalidales sensu lato (including Huaceae),[9][18] while others have found a different topology for the COM clade.

titled "L'Origine et le système phylétique des angiospermes", in which his Passionales and Polygalinae were derived from Linaceae (in Guttales), with Passionales containing seven (of eight) families that also appear in the current Malpighiales, namely Passifloraceae, Salicaceae, Euphorbiaceae, Achariaceae, Flacourtiaceae, Malesherbiaceae, and Turneraceae, and Polygalinae containing four (of 10) families that also appear in the current Malpighiales, namely Malpighiaceae, Violaceae, Dichapetalaceae, and Trigoniaceae.

To make a clear break with classification systems being used at that time, the Angiosperm Phylogeny Group resurrected Hutchinson's name, though his concept of Malpighiales included much of what is now in Celastrales and Oxalidales.