This document discusses the classification of weeds. It defines weeds as plants that interfere with human activities or welfare. Weeds can be classified according to their habitat as aquatic, terrestrial, or subterranean. They can also be classified based on their life cycle as annual, biennial, or perennial. Additionally, weeds are classified as monocotyledons or dicotyledons. Lastly, the document discusses classifying weeds according to their association with certain crops.

2. CLASSIFICATION
OF WEEDS

3. SUBMITTED TO:
Dr . Shankarnarayan sir
Department of Agronomy
Sericulture college Chintamani
Submitted by:
Anil Kumar. G.N
I BSc (Agri)
ID.No: ALC3004
Sericulture College Chintamani

4.  INTRODUCTION.
 DEFINATION OF WEEDS.
 CLASSIFICATION OF WEEDS.

5.  The definition of weeds is predicated on human
perception , desire and needs.
 A weed is a plant which interferes with human
activity or welfare.
 It is also defined as plant growing in a place
where it is not desired at a particular point in
time.

6.  Classification according to habitat.
weeds occur in crop lands , orchards
, forests. They may be aquatic , terrestrial
and subterranean.
Aquatic: These weeds grows in water.
Ex: masilea guadrifolia, and some
convolvulaceous plants are water
hyacinth, hydrilla, algae, reed grass etc.

7. Terrestrial: All mesophytic weeds.
Roots of these weeds remain concentrated in
20-30 cm depth from surface.
Subterranean: These weeds are not fully
subterranean , their roots , rhizomes , remain
underground and multiply.

8. Aquatic weeds
Terrestrial weeds

9.  Classification according to life cycle.
These may be annual , biennial or
perennial.
Annuals : They may mostly complete their
life cycle in a season.
Biennials : These weeds complete their life
cycle in 2 seasons/years.
Perennials: These weeds are found almost
every where in cultivated lands
, uncultivated lands , waste lands.

10. 
According to cotyledons weeds are classified
as monocotyledon or dicotyledon species.
The monocots are narrow leaved weeds of
grass family , dicots are broad leaved.

11. On this basis weeds may be woody , semi
woody , and herbaceous.
Herbaceous weeds are more common than
others. Ex : lantana camara, acacia arabica, are
common woody species.

12.  Weeds flora and their characteristics are different in
different types of crops . some may be common.
 According to their association they may be upland rice
association weeds , low land rice association weeds
, wheat association weeds, pulse association weeds. Etc
Ex: In mustard-cleome viscosa and cleome menaphylla.
In horse gram- tephrosia purpurea. In rice- O.sativavar
fatua .

13.  These may be absolute weeds , relative
weeds, rogues .
 Rogues means mixture of other variety in a
variety grown.

14.  Some weeds grow as parasites on other crops.
 They may be considered as loaders.
 These are cuscuta , orobanchae , striga, etc.