Euphorbiaceae

Plant Sex: Flowers unisexual, plants monoecious or dioecious.

Flowers: Two types: the first is the "Euphorbia" type - with the perianth very reduced and the flowers in a specialized inflorescence (cyathium, see below). The second is the "non-euphorbia" type with more typical flowers, sometimes with connate petals (Jatropha).

Inflorescence: Cymes or in Euphorbia and relatives, a CYATHIUM. Nectar glands often present on the rim of the cyathium (the bracts).

Fruits: Schizocarpic capsule splitting into 3 mericarps.

Habit: Extremely variable: annual or perennial herbs, shrubs, or (in the tropics) large trees. Many members succulent, esp. in S. Africa. Sap milky (latex) in some members.

Leaves: Commonly alternate and simple when present.

Examples:

Euphorbia - a large genus (1500 species). Some other genera, such as Chamaesyce and Pedilanthus, used to be in the genus Euphorbia but were split out.

E. cotinifolia. Flowering branch. Cyathia, develomental series. Cyathium dissected. Staminate flowers.
E. milii (crown-of-thorns). Habit of plant. Cyathia. L.S. of cyathium. Dissected cyathium.
E. pulcherima (poinsettia). Plant in flower.
E. corollata (flowering spurge). Inflorescences that appear to be individual flowers (pseudanthia). Cyathia, intact (left) and with female flower in L.S.
Three species of succulent Euphorbia: E. coerulescens (left), E. obesa (middle), E. trigona (right).

Ricinus

R. communis (castor bean). Habit of the plant. Close up of the staminate and carpellate inflorescences. Seeds.

Manihot

M. esculenta (cassava, manioc, tapioca). Vegetative plant. Rhizomes being sold in market in Puerto Rico. Flower.

Codaeum

C. variegatum (croton). Shrubs in cultivation. Closer view of staminate and carpellate inflorescences.

Hevea

H. brasiliensis (rubber tree). Rubber tree grove. Latex being collected from rubber tree.

SIUC / College of Science / Elements of Plant Systematics
URL: http://www.plantbiology.siu.edu/PLB304/Lecture16Malpig/Euphorbiaceae.html
Last updated: 29-Mar-08 / dln