EUPHORBIA

euphorbia, in botany, a large genus of plants from which the order euphorbiaceae takes its name. it includes more than 600 species and is of almost world-wide distribution. it is represented in britain by the spurges--small, generally smooth, herbaceous plants with simple leaves and inconspicuous flowers arranged in small cup-like heads (_cyathia_). the cyathium is a characteristic feature of the genus, and consists of a number of male flowers, each reduced to a single stamen, surrounding a central female flower which consists only of a stalked pistil; the group of flowers is enveloped in a cup formed by the union of four or five bracts, the upper part of which bears thick, conspicuous, gland-like structures, which in exotic species are often brilliantly coloured, giving the cyathium the appearance of a single flower. another characteristic is the presence of a milky juice, or latex, in the tissues of the plant. in one section of the genus the plants resemble cacti, having a thick succulent stem and branches with the leaves either very small or completely reduced to a small wart-like excrescence, with which is generally associated a tuft of spines (a reduced shoot). these occur in the warmer parts of the world as a type of dry country or desert vegetation. the only species of note are _e. fulgens_ and _e. jacquiniaeflora_, for the warm greenhouse; _e. cyparissias_ (the cypress spurge), _e. wulfeni_, _e. lathyris_ and _e. myrsinites_, for the open air.