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What are the Plant Groups?

Updated on December 31, 2012
Plants show a tremendous diversity but all share a few common characterisitics.
Plants show a tremendous diversity but all share a few common characterisitics. | Source

What are Plants?

Most of my pupils are ok with the idea that there are lots of different 'types' of animal - birds, reptiles, fish etc. What they have greater trouble with is the idea that there are also lots of different types of plant. Many will offer suggestions such as flowers, trees and bushes, but this is not a very scientific way of classifying the different types of plant.

I typically start this topic with a simple question:

What is a plant?

Children usually start by saying that plants do not move - this is a misconception. Plants can move, but not from their anchor point. If you watch a sunflower on a time-lapse film it is clear that the plant tracks the sun as it moves across the sky. Plants share the following features:

  • They contain chlorophyll and obtain most of their energy from the sun using photosynthesis
  • They are multicellular;
  • They possess cell walls made of cellulose;
  • Undergo alternation of generations;
  • Possess apical meristems, which the plants use to grow;
  • Can reproduce sexually (although many plants are capable of both sexual and asexual reproduction).

Within these common features, there is plenty of scope for variation. With over 200,000 species of plants on our planet it is vital that these plants are classified to help their study. Why study plants? That's easy! Plants are vital to our survival: they provide us with oxygen and food, as well as medicine, building materials and fuel. Without plants, life as we know it would be impossible.

Plants CAN move - time lapse

The Plant Groups

Name
Example
Key Features
Fern
Horsetails
Vascular Plants; reproduce using spores
Conifer
Giant Sequoia
Needle-shaped leaves, reproduce using cones and seeds
Flowering Plant
Water Lily
Vascular Plants; reproduce using flowers
Moss
Hairy-cap Moss
Non-vascular plants; reproduce using spores
Whilst this is not the true classification of plant groups, it does represent the most recognisable plant in each of the groups.

Pictures of Mosses

Mosses are not vascular plants and so lack roots, xylem and phloem. This means, however, that they can survive in areas with very little soil, or even on bare rock.
Mosses are not vascular plants and so lack roots, xylem and phloem. This means, however, that they can survive in areas with very little soil, or even on bare rock. | Source

Characteristics of Mosses

Mosses belong to a group of herbaceous plants called bryophytes. Bryophytes also include liverworts and hornworts and are likely the oldest true plant group on Earth. All bryophytes are non-vascular: they lack xylem and phloem, and do not possess true roots.

Mosses are the most familiar of the bryophytes and grow up to 50cm tall at some stages of their life cycle. Like all plants, they are full of chlorophyll which gives them a green colour, although this can be masked by other colours as the moss prepare to release spores.

Mosses:

  • Lack roots and can grow in very shallow soil or even bare rock;
  • Grow in damp and shady places only;
  • Have tiny leaf like structures that are often a single cell thick;
  • Lack xylem and phloem (they are non-vascular)
  • Reproduce using spores

Pictures of Ferns

Ferns reproduce using spores, just like mosses. Unlike mosses, Ferns are vascular - they possess true roots and xylem and phloem. This picture shows a young frond being unrolled.
Ferns reproduce using spores, just like mosses. Unlike mosses, Ferns are vascular - they possess true roots and xylem and phloem. This picture shows a young frond being unrolled. | Source

Characteristics of Ferns

Ferns represent a shift in power in the plant world. During the first 100 million years of plant evolution, non-vascular bryophytes dominated the globe. Ferns were the first group of seedless vascular plant to evolve; the plant kingdom has never looked back. Ferns developed the xylem, phloem and true root systems typical of all vascular plants.

Ferns are the most widely recognised of the seedless vascular plant group that also includes Lycophytes, whisk ferns and horsetails.

All Ferns

  • Possess large leaf like structures called fronds, often divided into leaflets;
  • Reproduce using spores (some species produce more than a trillion spores in their lifetime);
  • Have fully formed xylem and phloem;
  • Possess true roots that anchor the plant in the ground.

The Plant Kingdom Poster
The Plant Kingdom Poster

This poster summarises the differences between all of the different plant groups. I have one in my classroom!

 

Pictures of Conifers

Click thumbnail to view full-size
Conifers are vascular plants that reproduce using cones instead of flowers. The larger cones are the female variety...And the smaller cones are male.
Conifers are vascular plants that reproduce using cones instead of flowers. The larger cones are the female variety...
Conifers are vascular plants that reproduce using cones instead of flowers. The larger cones are the female variety... | Source
And the smaller cones are male.
And the smaller cones are male. | Source

Characteristics of Conifers

Conifers mark another paradigm-shift in the plant world - the evolution of pollen and seeds. Conifers were among the first plants to move away from spores and towards seeds. Conifers are known as Gymnosperms ('naked seed') because they do not encapsulate their seeds in ovariers.

Conifers dominate vast forested regions of the Northern Hemisphere, including the Tiger Belt. Here their evergreen* and hardy nature is invaluable in a region where the growing season is short and the winters long and harsh. When spring arrives, conifers have leaves ready to photosynthesise.

All Conifers:

  • Contain vascular tissue (xylem, phloem, roots);
  • Have needle-like leaves;
  • Reproduce using male and female cones;
  • Produce seeds, not spores.

*Whilst most conifers are evergreen, a few species are deciduous: the dawn redwood, tamarack and larch all lose their leaves each autumn/fall.

Pictures of Flowering Plants

Flowering plants are named for their reproductive organs - flowers. These diverse and delicate structures show amazing variation
Flowering plants are named for their reproductive organs - flowers. These diverse and delicate structures show amazing variation | Source

Characteristics of Flowering Plants

90% of all plant species on Earth are flowering plants (angiosperms). They form the staple diet of humanity (cereal crops such as wheat, barley, rice and maize are all flowering plants) and can be pollinated either by the wind, or by drafting in other animals to distribute their pollen (e.g. insects).

All Flowering Plants:

  • Possess specialised shoots for reproduction called flowers;
  • Encapsulate their seeds in fruits;
  • Are vascular plants (possess xylem, phloem and roots).

Flowering Plants can be further subdivided into Monocots and Eudicots.

Interviews with Plant Groups

Should Children be taught to identify different plants?

See results

Monocots and Eudicots - Characteristics

 
Monocot Characteristics
Eudicot Characteristics
Embryos
One cotyledon
Two cotyledons
Leaf Variation
Veins usually parallel
Veins usually netlike
Stems
Vascular Tissue Scattered
Vascular tissue in a ring
Roots
Fibrous system (no main root)
Taproot (main root) usually present
Pollen
Pollen grain with one opening
Pollen grain with three openings
Flowers
Flower petals in multiples of 3
Flower petals in multiples of 4 or 5
More than a quater of angiosperms are monocots (orchid, lily, barley) and over two thirds of angiosperms are eudicots (poppy, the pea, zucchini).

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    • profile image

      summerberrie 4 years ago

      Love this resource. Well written and organized.

    • TFScientist profile image
      Author

      Rhys Baker 4 years ago from Peterborough, UK

      Thanks, summerberrie! Glad to know I can still write properly!

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