The Malpighiales is a large and diverse order of more than 30 families, including Euphorbiaceae (spurges) and Passifloraceae (passion fruit, Adenia), both families including species of toxic but choice succulent plants and hardy plants of interest to the gardener.
The order also includes Linaceae (flax), Hypericaceae (St. Johns Wort), Rhizophoraceae (mangroves), Violalaes (violets) and Salicaceae (willows).
The Euphorbiaceae (spurges) include the commercially important rubber tree Hevea brasiliensis, the starchy root cassava (Manihot esculenta) and the castor oil plant (Ricinus communis.)
Millions of Poinsettias (Euphorbia pulcherrima) are propagated by the horticultural trade every year in time for Christmas and there are many frost-hardy non-succulent plants that make a fine display in the garden.
However it is the diverse array of succulent Euphorbias that are of special interest to the succulent plant collector, with growth habits that include caudiciforms, thorny stem succulents, shrubs and trees. The free-flowering Crown of Thorns Euphorbia milii is a popular window-ledge plant.