Leersia hexandra

Leersia hexandra
Conservation status
Secure (NatureServe)
Scientific classification
Kingdom:	Plantae
Clade:	Angiosperms
Clade:	Monocots
Clade:	Commelinids
Order:	Poales
Family:	Poaceae
Genus:	Leersia
Species:	L. hexandra
Binomial name
Leersia hexandra Sw.
Synonyms
Synonyms Asprella australis Asprella brasiliensis Asprella hexandra Asprella mexicana Blepharochloa ciliata Homalocenchrus angustifolius Homalocenchrus gouinii Homalocenchrus hexandrus Hygroryza ciliata Leersia abyssinica Leersia aegyptiaca Leersia angustifolia Leersia australis Leersia brasiliensis Leersia capensis Leersia ciliaris Leersia ciliata Leersia compressa Leersia contracta Leersia dubia Leersia elongata Leersia ferox Leersia glaberrima Leersia gouinii Leersia gracilis Leersia griffithiana Leersia luzonensis Leersia mauritanica Leersia mauritiaca Leersia mexicana Leersia parviflora Oryza australis Oryza hexandra Oryza mexicana Pharus ciliatus Pseudoryza ciliata Zizania ciliata

Leersia hexandra is a species of grass known by the common names southern cutgrass, clubhead cutgrass, and swamp rice grass. It has a pantropical distribution. It is also an introduced species in many regions, sometimes becoming invasive, and it is an agricultural weed of various crops, especially rice. It is also cultivated as a forage for .

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. It is an aquatic or semi-aquatic grass, and the erect stem parts may float in water. These stems can grow densely in aquatic habitat and become matted, forming what are often referred to as "carpets".

The leaf sheath has a fleshy base covered in white hairs and the ligule can be stiff and dry, becoming "papery". 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.

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Wikipedia