Asterids

Abstract Asterids constitute one of the major clades of the Powering plants (Fig. 1). It comprises more than 80,000 species or nearly one-third of all Powering plants. 7ey are grouped in 10 orders and about 100 families (1, 2). Two of the Ave most species-rich Powering plant families are asterids, the sun Power Family Asteraceae with 23,000 species and the coffee or madder Family Rubiaceae with about 13,000 species. 7ere are hundreds of economically important species within the asterids, and some families are particularly important sources for foods, spices, Pavorings, or drugs. Active chemical substances (e.g., alkaloids) are common in many species. themost important are coBee (CoZea arabica in Rubiaceae) and tea (Camellia sinensis in 7eaceae), which both contain caBeine and similar alkaloids. Tobacco (Nicotiana tabacum) with its active substance nicotine is a member of Solanaceae, a family that contains several other poisonous and hallucinogenic plants. Periwinkles (Catharanthus roseus) of the Apocynaceae yield potent alkaloid drugs, which have drastically lowered mortality in leukemia.