WEED FLORA AND WEED DISTRIBUTION IN RICE ECOSYSTEM

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WEED FLORA AND WEED DISTRIBUTION IN RICE ECOSYSTEM
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• Transplanted rice
• It is the traditional method of cultivating rice
  is flooding condition in which the young
  seedlings are transplanted from the nursery.
• The predominant weed in the transplanted rice
  field

Cynodon dactylon, Echinochloa colonum,
Dactyloctenium aegyptium and Chloris barbata
among the grasses and among the dicot weeds,
Alternanthra pungens, Portulaca oleraceae,
Eclipta alba and Tridax procumbens were the
predominant broad leaved weeds.
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• Echinochloa colona (L.) Link.

It is annual grass grows commonly in waterlogged
conditions belonging to the family Gramineae. It
is also called as jungle rice and in tamil it is
called as varnampul.
It grows up to a height of 60 cm. Leaf-blade 7.5
to 15 cm long, often blotched with purple or
almost black cross bands ligule 0,2-5(9) cm.
Inflorescence linear. Spiklelets ovoid-ellipsoid,
to 2mm with fruit caryopsis.
It is propagated by means of seeds. It is an
excellent fodder
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Echinochloa crus-galli (L.) Beauv.

• It is an annual grass belonging to the
  family Gramineae. It is a mimic of rice. It grows
  upto 37cm height with no ligule.Inflorescence an
  erect panicle with fruit ovate a elliptic grain.

It propagate by means of seeds.
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Eclipta prostrata L. (Syn. Eclipta alba Hassk.)
It is an annual broad leaved weed also called as
Karasaranganm in the family Asteraceae.  
It is diffusely branched stem is round and fleshy
with strigose hairs
Leaves opposite, sessile, linear and strigose..
Flower head is small, axillary and terminal.
Fruit is Achenes. Propagate by means of seeds
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Fimbristylis milliacea (L.) Vahl.
Belongs to Cyperaceae family. It is erect annual
sedge, with stem caespitoe to 30 cm ligule
absent. Inflorescence is compound and the fruit
is nut obovoid.
Propagation by means of seed.
It is common in wet land ecosystem
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Marsilea quadrifolia L. (Pteridophyta)
The water fern belongs to the family Marsileaseae
also called as Arai keerai in Tamil. It is an
Amphibious herb with procumbent rhizomes. Occurs
in marshy areas, also in rice fields and floating
in running water. The stem is long creeping
stolon, rooting at the nodes. Leaves are erect on
long petioles. Leaflets are 4, rather large,
obovate and entire on the margin.
Veins are many and forking. Propagate by means
of Stolons and spores
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Cynodon dactylon Pers.
In black soils and in dryland is a noxious weed
and once a field is infested with it, cultivation
becomes impossible. It is considered as one of
the ten worst weeds in the world and problematic
in all tropical and subtropical areas in dry land
and garden lands.
It belongs to the family Graminae (Poaceae) and
common name is Bahama Grass, Hariyali. In tamil
it is called as Arugampullu.
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• A perennial grass extensively creeping by means
  of scaly rhizomes or by strong flat stolons, very
  common in plains and hills sler and grows upto
  7.5 to 30 cm height
• The underground stems are hard, brittle, thick,
  pale white in colour and covered with short
  scale-leaves and occur at varying depth in soil.
  Leaves are linear, finely acute, 7.5 to 12.5 cm
  long, spikes 3 to 6. Spikelets are light green or
  purplish, sessile, laterally compressed,
  alternately 2-seriate, imbricate and 1-flowered.
• Grain is minute, oblong somewhat flattened,
  rounded on black. Propagated by through seeds and
  underground stolons.

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Chloris inflata Link (Syn. Chloris barbata Sw.)

• Chloris barbata belongs to the family Poaceae and
  also called as Mayil kondai pul. It is a tufed. A
  tufted perennial, commonly found as a weed in dry
  cultivated fields.

Culms upto 60 cm high. Leaves of 7.5 to 12.5 cm
long. Inflorescence with 6 to 15 digitately
arranged spikes, spikelets are usually purplish
in colour. Fruit is caryopsis. Propagation by
seeds. It is a good fodder grass
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Dactyloctenium aegyptium (L.) P. Beauv .
Dactyloctenium aegyptium (L.) P. Beauv is
buffalo grass in the family Poaceae. It is also
called as Kakkakalpal in Tamil.
It is an annual, grass growing in waste places
and dry cultivated lands.
Stem is Culms 10-62.5 cm high.
Leaves flat, 5 to 20 cm long, glabrous. Fruit is
Caryopsis. Propagation by seeds. Cattle graze
this readily
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Portulaca oleracea L. It is a succulent broad
leaved weed and it belongs to the family
Portulacaceae.
Common name is Indian Purslane.
In tamil it is called as Paruppu Keerai.
The main stem is short and erect bearing a number
of lateral branches which lie prostrate on the
ground, they grow to a length of 4-20 inches and
are green or reddish in color
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• The leaf-stalk is short. Flowers are without
  stalks, from 2-6 in number and are collected
  together in clusters at the s of branches. Sepals
  are 2 and fleshy they are united at the base and
  are free above.
• Petals are 5 and are yellow in color. Fruit
  is dry, dehiscing transversely by the upper part
  enclosed by the sepals, coming off as a lid
  leaving the lower part in the plant.
• Seeds are minute, blackish brown in color and
  are covered with concentric lines of tubercles.
  Propagation is by seed.

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Alternathera pungens H.B. K., (Syn.
Alternanthera echinata S.) An introduced
weed from tropical America, now common in dry
land, waste lands and roadsides. The plant
is gregarious in habit and produces roots at the
nodes for vegetative propagation.
Alternathera pungens Broad leaved weed is also
called as Khaki Weed and Mull ponnanganny in
Tamil.
It belongs to the family Amaranthaceae. It is a
biennial wed with trailing, diffusely branched
habit. The stem is round, hairy, slightly
tinged with pink the character of leaf is
opposite, elliptic, obtuse and flowers in
auxiliary spikes and small with fruit Achene.
Propagation by means of seeds.
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Trianthema protulacastrum. L.

Trianthema protulacastrum.L. is annual prostrate
herb belongs to the family Aizoceae.
In tamil it is called as Saranai.
Stem is round, striate, glabrous below and hairy.
Leaves are oppositve, petioled, petiole sheathing
at the base, obovate, in unequal pairs.
Flowers is solitary and sessile.
Fruit is capsule.
Propagation by means of seeds and cuttings.
It grows gregariously grows causing considerable
hinderance to normal cultivation.
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Cleome chelidonii L. f.
Cleome chelidonii is the broad leaved weed
belongs to the family Capparaceae.
It is a erect glabrous much annual herb growing
to a height of 30-60 cm.
Stem is covered with pointed hairs, leaf have
long pertioled, digitately compound, flower is
pink, bracteates with small bracts with capsule
fruit and propagate by seeds
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Parthenium hysterophorus L.
Parthenium hysterophorus L. is the generally
found in non-cropped situation but now a days a
weed of cropped field.
It belongs to the family Compositeae and commonly
called as congress weed and visha poondu in
Tamil.
It is a annual herb grows upto a height of 1.5
m.  
Stem is slunder with hairs, leaves are alternate
and sessile flower is white in colour with heads
many.
Fruit is called as achene. Propagated through
seeds.
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Ammannia baccifera (L.) m.
It Is an erect annual broad leaved herb growing
up to a height of 30 cm
It is Lythraceae family commonly called as
Blistering Ammania and in tamil called as
Neermael neruppu.
Stem is tetragonus, branches at the base are long
becoming shorter towards the top.
Leaves are small lanceolate, sessile and
opposite.
Flowers are axillary cluster calyx tubular
Fruit is a capsule and propagate by seeds.
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Direct seeded rice

• Direct Seeded Rice (DSR) in place of the
  traditional transplanted rice is a way to
  drastically reduce labor charges for nursery
  raising, puddling and transplanting.
• The predominant graminaceous weeds were
  Echinocloa crusgalli and Panicum sp. and weed
  species belonging to family cyperaceae viz.,
  Cyperus difformis and Cyperus iria.
• The broadleaved weeds included Ammania baccifera,
  Eclipta alba, Monochoria vaginalis and Marsilia
  quadrifoliata.

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Panicum repens L.
Panicum repens commonly called as Ginger Grass
and Inji pillu in tamil.  
It is a perennial grass, survive well under moist
condition.
Stem is Culms creeping at the base, rhizomatous,
60 to 150 cm long.
Underground stems are thick and hard, very much
resembling ginger.
Aerial branches are covered with pointed scale
leaves at the base.
Inflorescence is much branched terminal panicle
3-5 inches long. Spikelets is ovoid and pointed
on a short stalk and has four glumes.
Propagation by underground stems and grains.
It is much relished by cattle.
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Cyperus difformis L.
A common weed in paddy fields Cyperus difformis
is also called as Vatta Korai

• Belongs to family Cyperaceae.

A very common sler, weak plant found in marshes
and in shallow ponds stems tufted, 12.5 to 37.5
cm long.
Stem 8-40 cm height. Leaves flaccid, as long as
the stem bracts 2-3, 5 to 20 cm long.
Spikelets many, densely grouped into congested
globose heads glumes obovate, apex rounded.
Propagation by seeds.
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Cyperus iria L.
Cyperus iria L. belongs to the family Cyperaceae
and its tamil name is Oosikorai.
It is widely distriubtued species an all marshy
situations and also occurs as a very common weed
in paddy fields and in shallow ponds.
Belongs to the family Cyperaceae and its tamil
name is Oosikorai
It is erect glabrous annual.
Stem is 15 to 50 cm high, trigonous. Leaves up
to 42.5 cm long bracts 3-5, 5 to 25 cm long.
Spike consists of 5-15 spikelets spikelets
linear, oblong, yellow or pale-brown and glumes
plicate.Propogation by means of seeds.
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Monochoria vaginalis (Burm. f.)

• Monochoria vaginalis is a common wet land and
  broad leaved weed. It belongs to family
  Pontederiaceae.

A rooted aquatic herb, commonly growing in fresh
water and marshy areas. Root-stock short and
suberect. Flowers in racemes, usually blue
spotted with red and petaloid.
Fruit is a capsule. Propagation by seed and also
by root-stock
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Aerobic rice
Aerobic rice is a renewed way of growing rice in
non-submerged unpuddled condition in aerated
soils.
Aerobic rice varieties developed for the purpose
yield as much as irrigated puddled rice varieties
traditionally grown in rice paddies.
The predominant weed flora found were
Cynodon dactylon, Echinochloa colonum,
Dactyloctenium aegyptium and Chloris barbata
among the grasses and among the dicot weeds,
Alternanthra pungens, Portulaca oleraceae, Cleome
chelidoni, Parthenium hysterophorus, Eclipta alba
and Tridax procumbens were the predominant broad
leaved weeds.
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Semidry rice

• Semidry rice cultivation is growing rice under
  rainfed condition and later turning to lowland
  crop when rainwater is available from the tanks
  and/or from similar sources.
• The predominant weeds were

Cynodon dactylon and Echinochloa colona among
grasses, Trianthema portulacastrum and Portulaca
oleracea among broadleaved weeds and Cyperus
rotundus in sedges.
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