Edited by Ho Dinh Hai Long An - Vietnam Updated: 25/4/2015
1- Introduction to the Order Poales
1.1- Overview The Poales are a large order of flowering plants in the monocotyledons, and includes families of plants such as the grasses, bromeliads, and sedges. The earliest fossils attributed to the Poales date to the late Cretaceous period about 66 million years ago, though some studies (e.g., Bremer, 2002) suggest the origin of the group may extend to nearly 115 million years ago, likely in South America. The earliest known fossils include pollen and fruits. The flowers are typically small, enclosed by bracts, and arranged in inflorescences (except in the genus Mayaca, with solitary terminal flowers). The flowers of many species are wind pollinated; the seeds usually contain starch.
2.9- Family Juncaceae - Rush family + Overview The Juncaceae, the rush family, are a monocotyledonous family of flowering plants of eight genera and about 400 species. Members of the Juncaceae are slow-growing, rhizomatous, herbaceous plants, and they may superficially resemble grasses and sedges. They often grow on infertile soils in a wide range of moisture conditions. The most well-known and largest genus is Juncus. Most of the Juncus species grow exclusively in wetland habitats. A few rushes are annuals, but most are perennials. The leaves are evergreen and well-developed in a basal aggregation on an erect stem. They are alternate and tristichous (i.e., with three rows of leaves up the stem, each row of leaves arising one-third of the way around the stem from the previous leaf). Only in the genus Distichia are the leaves distichous. The rushes of the genus Juncus have flat, hairless leaves or cylindrical leaves. The leaves of the wood-rushes of the genus Luzula are always flat and bear long white hairs. The plants are hermaphroditic or, rarely, dioecious. The small flowers are arranged ininflorescences of loose cymes, but also in rather dense heads or corymbs at the top of the stem or at its side. This family typically has reducedperianth segments called tepals. These are usually arranged in two whorls, each containing three thin, papery tepals. They are not bright or flashy in appearance, and their color can vary from greenish to whitish, brown, purple, black, or hyaline. The three stigmas are in the center of the flowers. As is characteristic of monocots, all of the flower parts appear in multiples of three. The fruit is usually a nonfleshy, three-sectioned dehiscentcapsule containing many seeds. + Genera: 1- Andesia 2- Distichia 3- Juncus - Rush 4- Luzula - Woodrush 5- Marsippospermum 6- Oxychloe 7- Patosia 8- Rostkovia.
2.10- Family Mayacaceae + Overview TheMayacaceaeare afamilyof monocotyledonousflowering plantsin the order Poales, commonly known as thepipewort family. The family is small, with 7-8 species described in 1 genera. + Taxonomy - Genus The familyMayacaceaehas only one genus: Mayaca Mayacais agenusofflowering plants, often placed in its ownfamily, theMayacaceae.In theAPG II systemof 2003, it is assigned to the orderPoalesin the cladecommelinids. The Cronquist system, of 1981, also recognised such a family and placed it in the orderCommelinales in the subclassCommelinidae. The group is widely distributed inLatin America fromMexicotoArgentina, as well as in theWest Indies, the southeasternUnited States, and centralAfrica. - Species of the Genus Mayaca Eighteen or so species names have been proposed, but only 6 are generally accepted as distinct. 1- Species Mayaca baumiiGürke- In Congo-Brazzabille, Zaïre, Angola, Zambia 2- Species Mayaca fluviatilisAubl. - In southeastern United States from Texas to North Carolina; West Indies (Cuba, Jamaica, Trinidad); Latin America from central Mexico to Argentina 3- Species Mayaca kunthiiSeub. in C.F.P.von Martius & auct. suc. - In Venezuela, Brazil, Uruguay 4- Species Mayaca longipesMart.exSeub. - In Venezuela, Brazil, Colombia, the Guianas 5- Species Mayaca madida(Vell.)Stellfeld - In Costa Rica, Venezuela, Brazil, Colombia, the Guianas, Peru, Ecuador, Bolivia, Argentina 6- Species Mayaca wrightiiGriseb. - In Cuba
2.13- Family Restionaceae + Overview TheRestionaceae, also calledrestiadsandrestios, are afamilyof perennial, evergreen rush-likeflowering plantsnative to the Southern Hemisphere; they vary from 10 cm to 3 m in height. Based on evidence from fossil pollens, the Restionaceae likely originated more than 65 million years ago during theLate Cretaceous period, when the southern continents were still part ofGondwana. The family consists of tufted or rhizomatous, herbaceous plants,rush-likeorbamboo-likein overall appearance. They belong to a group of monocotyledonsthat includes several similar families, such as thesedges,rushes, andtrue grasses. They have green, photosynthetic stems and leaves that have been reduced to sheaths. Their flowers are extremely small and in spikelets, which in turn make up the inflorescences. Male and female flowers are on separate plants and, like grasses, are wind-pollinated. Plants in the family are distributed on all the southern continents -South America(1 sp., Apodasmia chilensis),Africasouth of the Equator and includingMadagascar(about 330 spp.) andAustralia(about 150 spp.) - inNew Zealand(four spp.) and widely distributed in Southeast Asia(one sp.). + Classification The Family Restionaceae has been recognized by most taxonomists. TheCronquist systemof 1981 also recognized this family and placed it in the order Restionales, in the subclassCommelinidaein classLiliopsidain divisionMagnoliophyta. TheAPG II systemof 2003 (unchanged from theAPG system, 1998), recognizes this family and assigns it to the orderPoales, in the cladecommelinidsof themonocots. The AP-Website (May 2006) assumes 58 genera and 520 species, which agrees well with the Flora of China.