Gramineae ~ Paspalum L.
Habit, vegetative morphology. Herb, less than 50 cm or 50–150 cm, annual or perennial, non-aromatic, non-parasitic. Bladder-shaped organs absent. Milky sap absent. Thorns absent. Plant habitat. Land plant or Water plant, rooted in the substrate, partially submerged. Underground parts. Underground parts without tuber-like structures. Rhizomes present, without tuber-like structures. Stolons present or absent, rooting at nodes, without tuber-like structures. Stems. Stems not hairy, round, erect or procumbent, hollow or solid, non-succulent. Leaves. Leaves one type present, large (more than 2 cm long/wide), not hairy on upper surface or on lower surface, hairy on upper surface or on lower surface, sessile, simple, narrow, alternate, evenly distributed on stem, margin entire, apex attenuate or acute, base attenuate or clasping or obtuse or rounded or truncate, parallel-veined, midrib not-prominent, surface not-waxy, non-succulent, glands absent, dots absent, papillae absent, hydathodes absent. Leaf sheath present, hairy or not-hairy. Stipules absent. Ligules present, not hairy, membraneous. Flowers, inflorescence. Flowers bisexual, grouped together in an inflorescence, terminal. Inflorescence not a spike or a head but other, compact, many (more than 5)-flowered. Flowers clustered, sessile or stalked, small (less than 2 cm), green or brown. Bracts present, not hairy. Spathe absent. Fruits. Fruit a nut or nut-like.
Notes: The stolons are sometimes purplish and hairy at the nodes; The stem (culm) nodes may be hairy or not hairy; The leaf sheaths may be purple; The leaves may have long white hairs at the base of the ligule; This grass may form mats; The inflorescence is made of flat or rounded spikelets and may be T-shaped. P. dilatatum Poir is an alternate host of a slug caterpillar (Paraso bicolor), an insect of rice in West Bengal. P. distichum L.: The detached stolons easily regenerate; The plant increases growth under zero tillage; This is a C4 plant and a serious weed. P. scrobiculatum L.: This is a serious weed.
Common names: P. conjugatum P.J. Bergius: Ya-hep, yanomnon (Thai).
Control methods: P. conjugatum P.J. Bergius: Chemical control with amitrole alone or followed by paraquat or MSMA (1.3 kg in 183 L of water) or diuron alone or followed by the above-mentioned herbicides. P. distichum L.: Manual control, but it is difficult because of the easily regenerating fragments; This plant is resistant to many pre-emergence herbicides but is susceptible to glyphosate (2.0 kg ai/ha) and moderately susceptible to paraquat; Thorough land preparation is effective, such as frequent early tillage and continuous flooding; Close spacing of rice plants shades out the weed; The most effective control is combining herbicides with good land preparation. P. scrobiculatum L.: Cultural control: early tillage and deep flooding.
Uses: P. conjugatum P.J. Bergius: Used as a fodder grass, but only when young because the spikelets tend to stick in the throats of livestock and cause them to choke; It is a good lawn grass because it is resistant to trampling; Concoctions from the leaves are used by the Iban in Borneo and in Papua New Guinea to treat cuts, wounds and sores, due to the presence of a haemostatic glucoside, paspaloside, which stops bleeding; In the Philippines, a decoction of fresh roots is taken for diarrhoea; It is also used in ointments for contusions, sprains, dislocations, in a vapor bath or as concoction for fever, flu, pneumonia, pleurisy (inflammation of lung tissue), fatigue and in an extract to relieve eye-injury. P. scrobiculatum L. var. bispicatum Hack. ex Merr.: It is used as a sand binder on gravel banks and cultivated in India for fodder and grain. P. distichum L.: Tribals feed the green grass to livestock and make it into hay and silage; The grass is found to be nutritious and enhances the milk yield of cattle; It is also a good soil-binder and helps to prevent soil erosion.
Image • pasdist.jpg. Paspalum distichum. • pasdisin.jpg. Paspalum distichum. • pscrobi.jpg. Paspalum scrobiculatum var. bispicatum. • pscroblv.jpg. Paspalum scrobiculatum var. bispicatum. • pscrobsh.jpg. Paspalum scrobiculatum var. bispicatum. • pscrobin.jpg. Paspalum scrobiculatum var. bispicatum. • pscrobin2.jpg. Paspalum scrobiculatum var. bispicatum.
Cite this publication as: ‘Naples, M.L. (2005). Weeds of Rain Fed Lowland Rice Fields of Laos & Cambodia. Unpublished MSc thesis, University of Leiden ’.
