PIPERALES

order of flowering plants comprising about 15 genera and approximately 2,000 species in three families. It belongs to the class that is known as Magnoliopsida (dicotyledons; characterized by two seed leaves). The Chloranthaceae and Saururaceae families together have fewer than 100 species; the remainder belong to the pepper family, Piperaceae (q.v.), which is widely distributed in the tropics of both hemispheres and is the source of pepper. The Saururaceae and Piperales are closely related, but the Chloranthaceae are a taxonomically isolated group; some authorities treat them as a separate order, Chloranthales. Inflorescences (flower clusters) of the Piperales are slender, spikelike, and covered with inconspicuous, closely appressed flowers. In the Saururaceae, the elongate cluster bends at its tip to suggest the fanciful appellation lizard's tail. Other features common to most species of this order include simple leaves, lack of sepals and petals, bisexual flowers (stamens and pistil in the same flower), and presence of one ovule per ovary chamber. The lizard's-tail family, Saururaceae, is native to North America and Southeast Asia. Its members are aromatic herbs, with creeping rhizomes (horizontal stems), inhabiting wet areas. Fragmentation of rhizomes in the lizard's-tail family assures vegetative propagation, but reproduction by seeds is the main method of species dispersal in the Piperales order. Even though individual flowers are small, floral spikes are showy in several species owing to the expanded, colourful bract that arises below each flower. Stamens usually number six, and the ovary chambers vary from one in the Piperaceae to several in the Saururaceae. This characteristic and the lack of wood in the Saururaceae distinguish the two families structurally. In a few species, stamens and pistils appear in different flowers. Seeds and fruits form in the usual manner of dicots. The drupe is the prevailing fruit type in the pepper family, whereas a dry, closed fruit characterizes the lizard's-tail family.