RESTIONALES

order of grasslike monocotyledonous flowering plants comprising four families, distributed mostly in the Southern Hemisphere, especially in southern Africa and Australia. Nearly all plants in the group exhibit reduced (simplified) flowers with a one- to three-chambered ovary containing only one pendulous ovule per chamber. There are one to three stamens (male pollen-producing structures) in all but the family Flagellariaceae, whose members have six. This family, which has two genera and about seven species, also differs in being composed of herbs and climbers with elongate leaves sometimes ending in a tendril, by which they climb. Pollination is mostly by wind. The largest family is Restionaceae, which has 25 to 35 genera and about 350 species. In the genus Restio (120 species) the leaves are reduced to sheaths around the stems, which are green and perform the functions of photosynthesis. The family Centrolepidaceae has about five or six genera and 35 or 40 species of small grasslike, sedgelike, or even mosslike plants. Two genera (Trithuria and Hydatella, with two species each) differ in being submerged aquatic plants. The family Hanguanaceae, with one genus (Hanguana) and only one or two species of robust, erect herbs, is perhaps misplaced in this order, but its relationships are not clear. The order is considered to represent an evolutionary condition somewhat between the lily order (Liliales) and the grass order (Cyperales).