Plant Diversity: Meaning, Importance and Conservation
Contents
Plant biodiversity is the variety of plant life on Earth, from tiny algae in a pond to tall forest trees. It includes the many plant species, the genetic differences within each one, and the plant communities they form. This variety feeds people and animals, provides medicines, and keeps ecosystems working.
Plants are one part of the wider web of life described in our main guide to biodiversity: meaning, types and threats. This page focuses on plants alone: what plant diversity means, how plants are grouped, why they matter, what endangers them and how they are protected.
What is the meaning of plant biodiversity?
Plant biodiversity is the total variety of plants found in a region or on the whole planet. Flora is the word for all the plant life of an area. The Botanical Survey of India (BSI) defines a flora as a systematic list of the plant species occurring in a given region.
Like all biodiversity, plant diversity can be seen at three levels:
- Genetic diversity: differences within one species. NCERT’s Class 12 Biology book says India has more than 50,000 genetically different strains of rice and 1,000 varieties of mango.
- Species diversity: the number and variety of plant species in an area, such as the trees, shrubs, ferns and orchids of one forest.
- Ecosystem diversity: the range of plant communities, such as mangroves, grasslands, deserts and alpine meadows.
Each level is explained with more examples in our guide to genetic, species and ecosystem diversity.
What are the main groups of plants?
NCERT’s Class 11 Biology chapter “Plant Kingdom” (Reprint 2026-27) describes five groups under the kingdom Plantae. The same chapter explains that fungi, and cyanobacteria (once called blue-green algae), are no longer placed in this kingdom.
| Group | Key feature | Examples |
|---|---|---|
| Algae | Simple, thalloid, chlorophyll-bearing; mostly aquatic | Spirogyra, Chlamydomonas, Volvox |
| Bryophytes | Live on land but need water for sexual reproduction; no true roots, stems or leaves | Marchantia (liverwort), Funaria, Sphagnum (mosses) |
| Pteridophytes | First land plants with vascular tissue (xylem and phloem); no seeds | Ferns, Selaginella, Equisetum (horsetail) |
| Gymnosperms | Seeds are naked, not enclosed in an ovary or fruit | Cycas, Pinus, Ginkgo |
| Angiosperms | Flowering plants; seeds are enclosed in fruits | Wolffia, Eucalyptus, mango, wheat |
Algae
Algae are simple plants whose body is a thallus, meaning it is not divided into root, stem and leaf. NCERT says algae carry out at least half of the total carbon dioxide fixation on Earth through photosynthesis. They also form the base of the food cycles of all aquatic animals.
Bryophytes
Bryophytes are the mosses and liverworts. NCERT calls them the “amphibians of the plant kingdom” because they live in soil but depend on water for sexual reproduction. Mosses and lichens are among the first organisms to colonise bare rock.
Pteridophytes
Pteridophytes include ferns and horsetails. NCERT describes them as the first land plants to possess vascular tissues. People use them for medicine, as soil-binders and as ornamental plants.
Gymnosperms and angiosperms
These two groups bear seeds. Gymnosperms such as pine carry naked seeds on cones. Angiosperms are the flowering plants, and NCERT calls them an exceptionally large group, ranging from the tiny Wolffia to Eucalyptus trees over 100 metres tall. The full contrast is set out in our guide to the differences between gymnosperms and angiosperms. If you sort plants by stem and height instead, see herbs, shrubs and trees with examples.
How rich is plant biodiversity in India?
India’s plant wealth is large, but the figure you quote depends on the source and on what it counts.
NCERT’s Class 12 Biology chapter “Biodiversity and Conservation” says nearly 45,000 species of plants have been recorded from India. This is the textbook figure for exam answers.
The Botanical Survey of India gives a fuller count. Its Annual Report 2022-23, citing Plant Discoveries 2021, puts plant diversity in India at 55,048 taxa. A taxon (plural taxa) is any named unit of classification, such as a species or a subspecies. BSI’s group-wise figures are shown below.
| Group (BSI) | Taxa in India | Share of India’s plant diversity |
|---|---|---|
| Angiosperms | 21,984 | 39.94% |
| Fungi | 15,602 | 28.34% |
| Algae | 9,008 | 16.36% |
| Lichens | 2,989 | 5.43% |
| Bryophytes | 2,800 | 5.09% |
| Pteridophytes | 1,314 | 2.39% |
| Virus/bacteria | 1,269 | 2.31% |
| Gymnosperms | 82 | 0.15% |
| Total | 55,048 | 100% |
BSI’s total includes fungi, lichens and microbes, which NCERT’s Class 11 chapter keeps outside the plant kingdom. So the two figures are not in conflict; they simply count different groups. The same annual report records 92 taxa newly discovered or newly recorded from India between April 2022 and March 2023.
For India’s animals, ecosystems and biogeographic zones, read the biodiversity of India: megadiversity, zones and species.
Why is plant biodiversity important?
Plants are producers: they make food from sunlight through photosynthesis. Almost every food chain on land and in water starts with them.
Food and everyday products
NCERT’s Class 12 book lists many direct gifts from nature: cereals, pulses and fruits, firewood, fibre and building material. It adds industrial products such as tannins, lubricants, dyes, resins and perfumes. NCERT’s Class 11 chapter notes that angiosperms give us food, fodder, fuel and medicines. It also names Porphyra, Laminaria and Sargassum among the 70 species of marine algae used as food.
Medicines
According to NCERT’s Class 12 book, more than 25 per cent of the drugs sold worldwide are derived from plants. It adds that 25,000 plant species contribute to the traditional medicines of native peoples. Exploring living things for such useful products is called bioprospecting.
Ecosystem services
Plants also provide free services. NCERT’s Class 12 book estimates that the Amazon forest produces 20 per cent of the oxygen in Earth’s atmosphere through photosynthesis. Newer scientific estimates are much lower, as our article on the ecosystem services of forests explains, so treat that figure as the textbook’s. Mosses form dense mats that soften falling rain and reduce soil erosion, NCERT’s Class 11 book explains. Many crops also depend on pollinators such as bees, birds and bats, which in turn depend on wild flowers.
Stability and future crops
NCERT reports that ecologist David Tilman found plots with more plant species showed less variation in total biomass from year to year. Genetic variety within crops matters too. Old crop strains may hold traits for disease or drought resistance that breeders can use. A wider look at these benefits is given in our article on why biodiversity matters.
What are the main threats to plant biodiversity?
NCERT groups the main causes of biodiversity loss as the Evil Quartet. Each one harms plants.
- Habitat loss and fragmentation. NCERT calls this the most important cause. It reports that tropical rainforests once covered more than 14 per cent of Earth’s land surface but now cover no more than 6 per cent.
- Over-exploitation. Collecting wild plants faster than they can regrow, for timber, fuel or medicine, shrinks wild populations.
- Alien species invasions. NCERT names carrot grass (Parthenium), Lantana and water hyacinth (Eichhornia) as invasive weeds that threaten native species in India.
- Co-extinctions. NCERT notes that in a plant and its partner pollinator that evolved together, the extinction of one invariably leads to the extinction of the other.
NCERT’s Class 12 book, citing the IUCN Red List (2004), records 87 plant extinctions among the 784 documented in the last 500 years. Pollution and climate change add further pressure. The causes and effects are covered in full in our guide to loss of biodiversity: causes, effects and solutions.
How can plant biodiversity be conserved?
Conservation works best when wild plants are protected in their homes and backed up elsewhere. In situ conservation protects plants in their natural habitat, while ex situ conservation keeps them in safe places away from it. Both approaches are compared in our article on in situ and ex situ conservation of biodiversity.
Protected areas and sacred groves
India protects its richest ecosystems as biosphere reserves, national parks and wildlife sanctuaries. Saving a whole habitat helps protect the plants in it, from canopy trees to mosses on the forest floor. Traditional sacred groves help too. NCERT notes that in Meghalaya, sacred groves are the last refuges for many rare and threatened plants.
Botanic gardens
Botanic gardens grow living collections of rare, endemic and useful plants. BSI states that ex situ conservation is one of its primary objectives and runs a network of gardens across the country. One of them, the Acharya Jagadish Chandra Bose Indian Botanic Garden in Howrah, was established in 1787, according to BSI. The Annual Report 2022-23 records that 165 rare, endemic, endangered, medicinal and economic plant species were introduced and maintained in BSI gardens.
Seed banks and laboratory methods
Seed banks store dried seeds at low temperatures so they stay alive for long periods. NCERT notes that seeds of different genetic strains of commercially important plants can be kept for long periods in seed banks. Plants can also be multiplied through tissue culture, which grows new plants from small pieces of tissue in a laboratory. BSI says some of its centres also store pollen and keep plant shoots at low temperatures.
What can students do?
- Grow native plants in school gardens instead of exotic ornamentals.
- Help remove invasive weeds such as Lantana during supervised clean-up drives.
- Never dig up wild orchids, ferns or medicinal herbs.
- Keep a simple record of the plants around your school, with local and scientific names.
The full set of methods, including laws and community action, is explained in our guide to biodiversity conservation methods.
Sources
Frequently asked questions
What is plant biodiversity in simple words?
Plant biodiversity is the variety of plant life in a place. It covers the many kinds of plants, from algae and mosses to ferns, conifers and flowering plants. It also includes the differences in genes within one plant species and the many habitats, such as forests and grasslands, that different plant communities form.
What are the five main groups of plants in NCERT?
NCERT's Class 11 Biology chapter 'Plant Kingdom' describes five groups: algae, bryophytes, pteridophytes, gymnosperms and angiosperms. Algae are simple and mostly aquatic. Bryophytes are mosses and liverworts. Pteridophytes are ferns and horsetails with vascular tissue. Gymnosperms bear naked seeds, and angiosperms are the flowering plants with seeds inside fruits.
How many plant species are found in India?
NCERT's Class 12 Biology book says nearly 45,000 plant species have been recorded from India. The Botanical Survey of India gives a wider figure. Its Annual Report 2022-23, citing Plant Discoveries 2021, puts India's plant diversity at 55,048 taxa. That total also counts fungi, lichens and microbes, so the two numbers measure different things.
Why is plant biodiversity important?
Plants feed almost every land food chain and give us cereals, pulses, fruits, fibre, timber and dyes. NCERT notes that more than 25 per cent of drugs sold worldwide come from plants. Plant cover also releases oxygen, holds soil and shelters animals. A wide range of plant varieties helps breeders develop crops that resist disease and drought.
How can we conserve plant biodiversity?
Plants are best protected in their natural homes, such as national parks, biosphere reserves and sacred groves. As a back-up, seeds are stored in seed banks, threatened plants are grown in botanic gardens, and rare species are multiplied through tissue culture. Controlling invasive weeds and stopping habitat clearance also protect wild plant communities.