Euphorbiales

Article By:

Cronquist, Arthur New York Botanical Garden, New York, New York.

Barkley, Theodore M. Division of Biology, Kansas State University, Manhattan, Kansas.

Last reviewed:January 2021

DOI:https://doi.org/10.1036/1097-8542.246000

A former order of rosid flowering plants, division Magnoliophyta (Angiospermae), in the class Magnoliopsida (dicotyledons). The order Euphorbiales consisted of the large family Euphorbiaceae (with about 7500 species) and 3 small satellite families (with fewer than 100 species among them). Modern-day classification systems no longer recognize the order. Instead, the plants formerly belonging to the order Euphorbiales have been assigned to the order Malpighiales. Euphorbiads include a group of few-ovulate, mostly simple-leaved plants in which the flowers have become unisexual and then undergone further reduction accompanied by aggregation. The trend toward reduction and aggregation culminates in the very large genus Euphorbia, with approximately 2000 species, in which the pseudanthium has a pistillate flower consisting of a naked, tricarpellate pistil surrounded by several staminate flowers (each of which consists of a single stamen). The illusion that this cluster constitutes a single flower is fostered also by the cup-shaped involucre, which often bears showy, petallike appendages. The Christmas poinsettia (Euphorbia pulcherrima) and the Pará rubber tree (Hevea brasiliensis) are well-known euphorbiads. Many African euphorbiads are spiny stem-succulents that resemble cacti in habit. Aside from the pronounced floral differences, euphorbiads have a milky juice, which cacti do not. See also: Cactus; Magnoliopsida; Malpighiales; Plant kingdom; Rosidae

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