Hunter's Woods PH

Montessori Biology

Parts of a Seed, Types of Seeds, and How Seeds Travel

Learn the different parts of a seed, the two main types of seeds, and the various methods of seed dispersal. Use the free worksheets at the end of the page to help reinforce learning.


  1. Parts of a Seed
    • Three main parts of a seed and their functions
    • Two layers of the seed coat
    • Parts of the seed embryo
  2. Types of Seeds
  3. How Seeds Travel
    • Two main types of seed dispersal
    • Five main modes of seed dispersal
    • Seeds dispersed by gravity
    • Seeds dispersed by ballistic
    • Seeds dispersed by wind
    • Seeds dispersed by water
    • Zoochory
      • Epizoochory
      • Endozoochory
      • Other types of zoochory
      • Seeds dispersed by animals
  4. Worksheets

Parts of a Seed

What are the three main parts of a seed and their functions?

The three main parts of a seed are the embryo, endosperm, and the seed coat.

The embryo is the “baby plant” produced during fertilization. It contains the tissues that later become the leaves, stem, and roots of the plant.

The endosperm surrounds the embryo, protecting it and serving as a source of nourishment. It is made up mostly of starch, as well as oil and protein.

The seed coat is the outer covering of the seed. It is usually hard and protects the seed from damage. It also prevents: (1) loss of water, (2) entry of parasites, and (3) germination during unfavourable environmental conditions.

The cotyledon (seed leaf) is sometimes mentioned as another main part of the seed but, strictly speaking, it is actually part of the embryo.

In some plants (such as peas), the mature seed does not have an endosperm because it was used up during the development of the embryo. In these cases, food storage becomes the role of the cotyledon.

What are the two layers of the seed coat?

The outer, thicker layer of the seed coat is called the testa.

The inner, more delicate layer is called the tegmen.

Other parts of the seed coat:

  • The point where the seed is attached to the ovary wall is called the hilum.
  • The tiny opening in the seed coat is called the micropyle. It is carried over from the ovule; the micropyle is where the pollen enters in order to fertilize the egg. Later, when the seed germinates, the micropyle is where the radicle comes out.

What are the parts of the seed embryo?

The seed embryo is made up of:

  • the radicle, the embryonic root;
  • the embryonic shoot (hypocotyl, epicotyl and plumule); and
  • the cotyledon(s), the seed leaf.

Types of Seeds

What are the two types of seeds?

Seeds are differentiated according to their number of cotyledons (seed leaves).

The two main types of seeds are the:

  • monocotyledons (monocots) – those with embryos that have only one cotyledon; and
  • dicotyledons (dicots) – those with embryos that have two cotyledons.

How Seeds Travel

What are the two main types of seed dispersal?

Seed dispersal is divided into:

  • autochory – when plants disperse their own seeds without help from another thing
  • allochory – when seed dispersal is through a secondary agent such as wind, water, or animals

What are the five main modes of seed dispersal?

The five main modes of seed dispersal are through gravity, ballistic, wind, water, and animals.

What types of seeds are dispersed by gravity?

Gravity causes fruits to fall from the plant when ripe. The seeds can then grow where they fall or be carried away. Seeds that are dispersed this way include those of apples, coconuts, passionfruit, and those with harder shells.

What types of seeds are dispersed by ballistic?

Some fruits have a built-in line of weakness that eventually splits (dehiscence) and allows it to expel seeds. Plants that disperse seeds this way include the dwarf mistletoe, exploding cucumber (or squirting cucumber), euphorbia, geranium, hairy bittercress, impatiens, and witch hazel.

What types of seeds are dispersed by wind?

Plants with seeds or fruits that can float and flutter away include dandelions, maples, and tumbleweeds.

What types of seeds are dispersed by water?

Plants that use water for seed dispersal include water lilies, palm trees, and mangroves.

What is zoochory?

Seed dispersal by animals is called zoochory.

What is epizoochory?

Epizoochory is when seeds are transported on the outside of animals, such as when burr sticks to an animal’s fur (or someone’s clothes) and is carried away by the animal.

What is endozoochory?

Endozoochory is the dispersal of seeds through ingestion by animals, mostly birds and mammals.

What are the types of zoochory?

Aside from epizoochory and endozoochory, which are explained above, other ways that animals carry out seed dispersal include:

  • seed predators – when rodents such as squirrels, and even some birds, help disperse seeds by hoarding them in well-protected hidden caches; if left uneaten, the seeds grow into new plants
  • seed spitting – by some rodents
  • diplochory – when dung beetles, in the process of collecting dung, disperse seeds from clumps of feces
  • myrmecochory – seed dispersal by ants
  • chiropterochory – seed dispersal by bats
  • malacochory – seed dispersal by molluscs, mostly terrestrial snails
  • ornithochory – seed dispersal by birds
  • saurochory – seed dispersal by non-bird sauropsids
  • anthropochory – seed dispersal by humans

What types of seeds are dispersed by animals?

The plants that disperse seeds by epizoochory (on the outside of animals) include:

  • flax, plantain, some crucifers – sticking to animals using mucus in their seed coats
  • twinflower, nightshade – through sticky hairs or hooks on their fruits
  • common agrimony – has persistent calyxes with hooks
  • wood avens – has persistent styles with hooked tips
  • mule grab, African grapple plant – have trample burrs that lodge between the hooves of large grazing animals
  • other burr-bearing plants such as American lopseed, beggar ticks, burr chervil, cleavers, cocklebur, greater burdock, longspine sandbur, puncturevine, Queen Anne’s lace, sweet cicely

The seeds of most tree species are dispersed by endozoochory (ingestion by birds, mammals, and other animals).

Seeds Worksheets

Note on the Worksheets

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Parts of a Seed: Worksheet for Kindergarten and Grade 1

Parts of a Seed: Worksheet for Kindergarten and Grade 2 and Grade 3

Types of Seeds: Worksheet

How Seeds Travel: Worksheet on Methods of Seed Dispersal

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