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''Leersia hexandra'' is a species of grass known by the common names southern cutgrass, clubhead cutgrass, and swamp rice grass.〔(''Leersia hexandra''. ) Pacific Island Ecosystems at Risk (PIER).〕 It has a pantropical distribution.〔(''Leersia hexandra''. ) Germplasm Resources Information Network (GRIN).〕 It is also an introduced species in many regions, sometimes becoming invasive, and it is an agricultural weed of various crops,〔 especially rice.〔CABI. (2013). (''Leersia hexandra''. ) In: Invasive Species Compendium. Wallingford, UK: CAB International.〕 It is also cultivated as a forage for livestock.〔(''Leersia hexandra''. ) FAO.〕 ==Description== This species is a perennial grass growing from rhizomes and stolons. The hollow stems are decumbent and creeping and root easily where their nodes contact the substrate. They produce erect shoots that can exceed one meter tall.〔〔(''Leersia hexandra''. ) Flora of China.〕 It is an aquatic or semi-aquatic grass, and the erect stem parts may float in water.〔Pyrah, G. L. (''Leersia hexandra''. ) Grass Manual. Flora of North America.〕 These stems can grow densely in aquatic habitat and become matted, forming what are often referred to as "carpets".〔〔〔(''Leersia hexandra''. ) In: ''Flora of West Tropical Africa'' vol. 3, part 2. 1972. JSTOR Global Plants.〕 The leaf sheath has a fleshy base covered in white hairs and the ligule can be stiff and dry,〔 becoming "papery".〔(''Leersia hexandra''. ) Center for Aquatic and Invasive Plants. University of Florida IFAS.〕 The leaves have sharp-pointed blades up to 30 centimeters long which are flat or rolled, the edges sometimes rolling at night or when the blade dries.〔 The blades are sometimes hairless,〔 but are usually coated in very rough hairs, making them so rough to the touch that they are "unpleasant to handle".〔 They also have very sharp edges,〔 and the midrib has backward-facing, spiny hairs that give it a cutting edge. The "retrorsely spinulose midrib of the leaf can inflict most painful lacerations".〔 The panicle is narrow or spreading and erect or nodding, and up to about 12 centimeters long. The branches are almost fully lined with overlapping spikelets each up to half a centimeter long.〔 The spikelets may be greenish or purplish in color,〔 or sometimes tinged with orange or brick red.〔 They are surrounded by white or purplish bracts that have characteristic comb-like hairs along their greenish nerves.〔 The flower has six stamens.〔 After the spikelets fall, the panicle branches have a zig-zag shape.〔 Fertile seed is rarely produced and the grass commonly reproduces vegetatively by sprouting from the rhizome or the nodes on the stem.〔 Large stands of the grass are often clones.〔 This grass looks very similar to rice and other species of the genus ''Oryza''. It is a member of the rice tribe Oryzeae and sometimes grows in rice paddies.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Leersia hexandra」の詳細全文を読む スポンサード リンク
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