|Classification of weeds with examples|
A. According to origin:
1. Alien (foreign in origin): Argemone mexicana (Shialkata – Mexico), Eichhornia crassipes (Kachuripana – Germany).
1. Kharif Weeds: Those which complete most of their life cycle in kharif season (April – September). Eg. Aeschynomene aspera(Bhat shola), Digitaria ischaemum (Khudey anguli ghash), Fimbristylis miliaceae (Joina), Cyperus difformis (Sabuj nakfuli), Digitaria sanguinalis (Anguli ghash), Lichinodloa sp. (Shama).
1. Annual Weeds: Annual weeds complete their life cycle in a year or less. They propagate by seeds. Normally, they are considered easy to control. Eg. Chenopodium album (Bothua), Eleusine indica(Chapra).
b. Bulbous perennial: Propagate through underground parts like bulbs, bulbils and tubers. Eg. Allium canadense (Wild onion)
1. Terrestrial Weeds: Weeds which grow in land only. Eg. Durba, Mutha, Chapra, Bothua etc.
a. Submerged weed: Weeds which grow under the water. Eg. Hydilla, Verticillata.
b. Emerged weeds: Weeds which roots are anchored in soil under water but some parts of it above the water. Eg. Sagittaria sagittafolia (Shaluk)
c. Floating weeds: Weeds which float above the water having no connection with any part of it with the soil. Eg. Kachuripana, Topapana etc.
· Free floating: Topapana (Pistia stratiotes)
1. Absolute weeds: Weeds which are considered as weed whenever they grow. Eg. Durba, Mutha, Shama etc.
1. Narrow leaf:
a. Grasses: Grasses are the member of family Poaceae or Gramineae. They are monocotyledonous weeds. Stem are hollow, simple, prostrate and straight. Leaves are simple, alternate, venation parallel. Eg. Cynodon dactylon, Elusine indica, Imperata cylindrica.
b. Sedges: Sedges are the member of family Cyperaceae. Stem are triangular or round, hollow, leaves are straight. Eg. Cyperus rotundus, C. esculentus
2. Broad leaf:
Broad leaf weeds are dicotyledonous plants. Leaf may be compound or simple. Venation reticulate. Eg. Chenopodium album, Xanthium italicum (Ghagra)
1. Acid soil weeds
2. Alkaline soil weed; Eg. Dandalin
1. General weed: Those which are less harmful, easy to control, produced less number of seeds.
1. Facultative weeds: Weeds which primarily grown in wild communities but after escape to cultivate field associating themselves closely with human affair. Eg. Opuntia spp.,
2. Obligate weeds: Weeds which grow only in cultivated field associated themselves closely with human affair. Eg. Shama, Bothua.
1. Herb: Cynodon dactylon, Cyperus rotundus
2. Shrub: Datura stramonium, Polygonum hydropiper (Bishkatali)
K. According to dependence on other hosts:
1. Total parasitic: Cuscuta reflexa (Dodder)
3. Independent: Cyperus rotundus.
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