Question

An American plant, which had become troublesome waterweed in India is:
(A) Typha latifolia
(B) Trapa bispinosa
(C) Cyperus rotundus
(D) Eichhornia crassipes

Answer 1

Hint: A weed is a plant that is not required in a particular situation. In simpler terms, weeds are plants in the wrong place. They have no botanical significance because if a weed, when grown in a situation where it is required, then it’s no longer considered a weed. It grows and reproduces aggressively.

Complete answer:
Weeds are the species that can survive in diverse environments and can reproduce quickly. Certain weeds have an adaptation to a ruderal environment where soil or vegetative cover has been damaged. For a weed community to dominate, the nature of the habitat and its disturbances play an important role.

Many times, weeds are grown intentionally in the gardens or in any other setting, where they are called Beneficial weeds which include Wildflowers. Weeds can be advantageous in many ways, for example, weed such as Dandelion is edible and also used in herbal medicines. Weeds attract many beneficial insects. Weeds also improve soil fertility.

But most of the time, weeds compete with voluntary crops with food and fiber production. They interfere with competing for the resources that plant utilizes like sunlight, water, nutrients. They provide shelter for animal pests that can be dangerous to our voluntary crop. They cause root damage to road surfaces, drainages, and block streams.

Recently, an American weed named Water Hyacinth also known as Eichhornia crassipes causes a lot of problems to aquatic species. Its uncontrolled growth covers the lake entirely and blocks the sunlight for aquatic plants and also kills water and fishes due to oxygen deficiency in water.

Typha latifolia is a herbaceous weed which is used in Manganese and Vitamin K supplements. Hence is a beneficial weed.

Trapa bispinosa is important for Ayurvedic medicine which is used in gastric and liver problems. Hence is also a beneficial weed.

Cyperus rotundus is used as an astringent, antispasmodic, and in treating skin disease like eczema and scabies. So, it is also a beneficial weed.

So, the correct answer is Option (D) Eichhornia crassipes.

Note: Weeds are undesirable plants, so weed control is very important for agriculture. They can be managed chemically and non chemically. Non-chemical methods include plowing, surface scuffling, and prevention of seed accumulation. Chemical methods are usually avoided because of the serious health effects of chemicals used on food crops.